-NRLF
GIFT OF
DEMONSTRATION OF THE FUNCTION OF
THE NKTUOMOTOR APPARATUS IN
EUPLOTES BY THE METHOD
OF MICRODISSECTION
A THESIS ACCEPTED IN PARTIAL SATISFACTION OF
THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY
AT THE UNIVERSITY OF CALIFORNIA
BY
CHARLES VINCENT TAYLOR
DECEMBER, 1918
UNIVERSITY OF CALIFORNIA PUBLICATIONS
IN
ZOOLOGY
Vol. 19, No. 13, pp. 403-470, plates 29-33, 2 text figures October 23, 1920
DEMONSTRATION OF THE FUNCTION OF
THE NEUROMOTOR APPARATUS IN
EUPLOTES BY THE METHOD
OF MICRODISSECTION
BY
CHARLES V. TAYLOR
UNIVERSITY OF CALIFORNIA PRESS
BERKELEY
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Vol. 17. 1. Diagnosis of Seven New Mammals from East-Central California, by Joseph
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fornia, by Hilda Wood Grinnell. Pp. 9-10.
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:;. 8p> :-pes platyceplialus, a New Alpine Salamander from the Yosemite
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5. Habits and Food of the Roadrunner in California, by Harold C. Bryant
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July 1917 *^
UNIVERSITY OF CALIFORNIA PUBLICATIONS
IN
ZOOLOGY
Vol. 19, No. 13, pp. 403-470, plates 29-33, 2 text figures October 23, 1920
DEMONSTRATION OF THE FUNCTION OF
TIIK NKU.'O.MOTOU A IM'A U'ATTS IN
BUPLOTES IJV TIIK MKTIIOI)
OF MI(M?()I)ISSK(TION
BY
CHARLES V. TAYLOR
CONTENTS
I'ACiE
Introduction
Acknowledgments -..
Mi'tliod anil material
Moist chambers
Binocular microscope
(llass needles
Control
Staining
Material 417
The living organism 418
Endoplasm *"
Ectoplasm 42
Macronueleus
Micronucleus
Contractile vacuole
Anal aperture
Cirri
Membranelles 426
Xeuromotor apparatus '-'
Movements 428
Experimental
Pellicle 431
Fibrillar system 432
Transections 435
Excisions - 439
Incisions 441
Discussion 444
Summary 456
Literature cited _ 458
Explanation of plates 462
; ,,\, -\\Uiviversitij of California Publications in Zoology [VOL. 19
INTRODUCTION
Protozoa are commonly regarded as representatives of the most
primitive and simplest forms of life. The most salient feature of the
phylum is conceded to be their unicellularity. each individual being
the morphological equivalent of a single cell. That these characteristics
indiscriminately applied to this very large and diversified group of
organisms are not only inadequate but somewhat misleading is par-
ticularly evident from several recent investigations on various flagel-
lates and ciliates. The results of these researches point toward com-
plexity rather than simplicity and stimulate inquiry into the nature
and function of certain intracytoplasmic structures that these animals
possess, which may indicate an organization more highly evolved than
is usually assumed.
These structures in both flagellates and ciliates are intimately asso-
ciated with ectoplasmic organelles (flagella, cilia, cirri, etc.), a fact
which strongly suggests that they share some role in the animal's
motor mechanism. Accordingly, investigators are generally agreed in
designating the structures with their attached organelles "the motor
apparatus. ' '
Of the organisms possessing such a motor apparatus a larger
number of flagellates than of ciliates has been studied and compara-
tively described. In the former class a series has been worked out that
indicates a progressive evolution of this mechanism. A simple type
of motor apparatus appears in the biflagellate stage of the soil amoeba,
Xiiii/Jtrin f/ruberi (Schardinger). It consists of two flagella attached
to a basal corpuscle, the blepharoplast, which in turn is connected by
a fine fibril to the nucleus. This organism spends most of its excysted
life as an amoeboid trophozoite, but it may become transformed for a
brief period of twenty-four hours or less into a very active flagellate.
This interesting change has been described by "Whitmore (1911),
Alrxeieff (1912), and more completely by Wilson (1916), who has
shown that variations in temperature, media, and other factors may
induce the change. The actual transformation may be followed in
living forms and its stages analyzed in fixed material.
It was thus observed that the motor apparatus arises by an out-
growth from the karyosome. "presumably from the centriole," Wilson
Tiiiilur: Neuromotor Apparatus in Ki/iilntix 405
slates. "which crosses the clear unclear /.one. emerges through the
nuclear membrane" whence arises a plastic thread, the rhizoplast, that
emls near the periphery in the blcpliarnplast. The two tlairdla grow
out from this blepharoplast.
The origin of the apparatus from the centriole is not clearly estab-
lished. This centriole can be seen within the karyosome during the
entire development of the liagclla. although its division may give rise
to these structures. Dr. Swexy (101(>) offers a critical discussion of
this point.
A less primitive motor apparatus is met with in Prowazekia
lai-l<>tix
Sharp i 1!M-1 ' was the tirst to succeed in tliis endeavor. Working
upon a parasitic ciliate. l>ii>li 'ni) oesophageal fibers, and (7) a circumoesophageal ring.
The relation of these parts to the organelles with which they are asso-
ciated is best described in Dr. Sharp's own words. In a specimen
stained with his modification of Mallory's connective tissue stain, the
so-called motorium was first observed as a mass "which had stained
rather intensely and showed by transmitted light the same bright red
color which was noted in the case of the micronucleus. Further in-
vestigation along this line revealed the fact that not only was this mass
constant but (1) that it was connected dorsally, by means of a delicate
strand, i.e., dorsal motor strand, with the bases of the dorsal mem-
branelles. also a branch strand ran along the base of the inner dorsal
408 I'nh'irxi/ij af C/ilijnniin I'lililii-uli/mn in Zoology [VOL. 1!)
lip, i.e., the dorsal lip strand; ('2) that a fine strand, the ventral motor
strand, ran from it to the bases of the adoral membranelles, also that
a branch strand left this ventral motor strand and passed along the
base of the inner adoral lip, the adoral lip strand, and that many well-
defined fibers passed from it, following the contour of the operculum
toward the right to become lost in the immediate vicinity of the base
of the right skeletal structure. These are the opercular fibers. Most
interesting of all, however, was Hie apparently perfectly definite con-
nection with a ring of the substance surrounding the oesophagus at
just about the level of the outer adoral furrow. This ring, which is
designated as the circunioesopliageal, as well as all of the fibers
described as leaving the motorium, showed in all regions the same
bright red color. Other fibers also staining bright red are found in the
oesophageal walls. These are found in the oesophageal walls. These
are called the oesophageal fibers, but thus far it has not been definitely
decided whether they take their origin from the motorium or directly
from the circumoesophageal ring, probably the latter, however"
(Sharp, 1914, p. 83).
Inasmuch as this complex system of motor mass and strands is
intimately associated with the motor organelles, one is justified here,
as in the case of the flagellates, in regarding these structures as a part
of the animal's motor mechanism, whatever their specific role may be.
But just what is their specific function? Three possibilities were
obvious: (1) this intracytoplasmic system may be skeletal, for sup-
port; (2) it may be muscular, the strands representing primitive con-
tractile fibrils; or (3) these strands may have conductive properties
with the motorium functioning as a coordinating center for impulses
passing over the primitive neural fibrils. After weighing the evidence
which his investigations had disclosed, Sharp concluded that the last
hypothesis was in nearest agreement with the facts.
The skeletal hypothesis, adopted by Braune (1913) for a similar
system found in Ophryoscolex purkynjei of the same family as Diplo-
dinium ecaudatum, was believed by Sharp to be insufficient for his
species. The diminutive size of the "motor mass," its nonconformity
in shape to the particular region of its location, and the want of
attachment of the several strands to any fixed structures were con-
ditions unfavorable to such an interpretation.
Nor did it seem probable that the mechanism is contractile in
function. If it were so, it should appear attached to fixed structures,
on the one hand, in order to affect movable structures, on the other.
'1'iii/lnr: .\i iir/nii/iliir Ai'/Kii-nh/x in Kni>l<>lis 40!)
whirl) is lint the r;lsr. Furthermore. the organelles with which the
strands are associated arc never translated in "the direction of the
strands leaving the motorinm. hut rather in a direction at right angles
to the course of the tihers. thus inilitat ing against a contractile func-
tion for the tihers" (Sharp. 1!14. p. 81
The perfect coordination in the activity of mobile parts, all of
which are supplied liy strands from the centrally placed inotoriuin.
and the advantageous location of the system to function "as a center
nf motor coordination in an animal which is exceedingly active, exceed-
ingly responsive to external stimuli and one, moreover, which exhibits
a high decree of selective feeding." are phenomena which could In-
most satisfactorily explained on the hypothesis that this apparatus
functions as a primitive type of nervous system whose coordination
is i fl'ected through the central motor mass, the motorium. Accord-
ingly, Sharp gave to this system the name " neuromotor apparatus."
fii a fresh-water ciliate. K>ii>li>l( CitHI'iii-iiiil I'l/liUni/ irni.f ill Zon/u//;/ (Vol. 19
the pharynx. The remaining external organdies embrace eighteen
styliform cirri. Of these, four are caudal and fourteen ventral in
position. The right anterior ventral surface bears nine cirri, of which
six are termed frontal and three ventral cirri. The remaining five of
those ventral in position, known as anal cirri, are the largest and
longest and are the most important. These have their origin at the
ends of the five ventral grooves about twenty-five microns from the
posterior end, and extend backward beyond the caudal margin of the
body.
All the cirri were observed by Yocom, in agreement with Maupas
(1883) and Griffin (1910), to be composed of cilia with distinct basal
granules. The component cilia are imbedded in a dense plate of ecto-
plasm just beneath the pellicle, the plate serving as a firm support for
the cirrus. Now from the basal plate of each anal cirrus there extends
a fiber toward the anterior end. These fibers were first seen and
figured by Maupas (1883) who briefly described them as joining the
five anal cirri and extending forward to converge and unite into a
single thread which disappeared near the anterior end of the animal.
In 1903 Prowazek found similar fibers in Euplotes liarpa and Griffin
(1910) described such fibers for E. worc.esteri. Yocom, however, was
able to trace the fibers in E. patella farthe- forward to where they join
one end of a very small bilobed body, "the motorium." "It was first
seen as a dark body in animals stained with iron-alum haematin, lying
close to the right anterior corner of the triangular eytostome. In
specimens which are well destained this body is seen to be composed of
very fine granules closely grouped together, but if too dark it has the
appearance of an almost homogeneous body. "When stained with
Mallory's stain the motorium becomes bright red from the acid fuchsin
and lacks the granular appearance characteristic of specimens colored
with haematin. Plate 14. figure 5 (mot.) shows that this motor mass
does not have a smooth contour, but rather that it has ragged edges
with processes extending out into the surrounding ^ctoplasm" (Yocom,
1918, p. 355). The motorium is about eight : herons long and. as
figured, about one-fourth as wide as it is long. Joining its left end are
the five long fibers from the anal cirri. These fibers converge and
appear to unite with the motorium as a single strand.
From the right end of the motorium another fiber, the anterior
cytostomal fiber, was found to pass anteriorly and to the left along
the proximal border of the oral lip and the bases of the membrane! Irs
throughout the entire series. Within the oral lip was observeci a
Tiii/lor: Neuromotor Apparatus in Eni>lnttx 411
conspicuous "lattice-work structure" whose bases, like those of the
iiieiiihraiiclles. very closely approximate the cytostomal fiber. Thus is
formed Yocom, 1918) "an unbroken fibrillar complex between the
heavy anal cirri which are used chiefly in locomotion and the inein-
hrauelles of the adoral /one which function as organs of food getting,
organs of locomotion, and as tactile structures." Several finer and
shorter fibers pass out from the base of each of the other thirteen cirri
but Yocom found no indication that these libers connect with any part
of the complex uniting the membrancllcs. the lattice-work structure
of the oral lip, and the anal cirri.
Tlu* anatomical continuity of this fibrillnr system, its selective stain-
ing properties, the anterior, free position of the motorium and the
intimacy of its several branches with the large, vigorous anal cirri,
with the peculiar diffused lattice- work of the oral lip and with the ever
active membranelles. these were significant features which strongly
suggested that the whole, unique arrangement must have a function
more highly specialized than merely that of support or even one of
contractility. Rather, the system here, as the one in Diplodin'nun
iriimliih/i/i. should be regarded as possessing properties of conductivity
functioning to coordinate the movements of the organs with which it
is associated. It, accordingly, was also designated "neuromotor
apparatus."
The morphological evidences which Yocom 's researches have yielded
lend strong support to this "neuromotor" hypothesis. Yet. however
significant may be the foregoing evidences favoring the function of
conductivity for this novel apparatus in Euplotcs, to establish this or
any interpretation of organic function, methods beyond the bounds of
morphological inquiry must be introduced. In this endeavor, the in-
vestigator enters another field of labor, viz., that of experimental
biology, the need and importance of which has, in comparatively recent
years, become more fully recognized among biologists. Phenomena
studied and described by the morphologists are of primary importance.
A comprehensive i> owledge of a structure and its relations is pre-
requisite to an understanding of its function. But functions can not
be ascertained by exploring and mapping parts. Experimental means
must also be provided, otherwise further progress is impeded and may
even be rendered impossible.
In view of this and because of the important significance that
attends the theory of the presence in certain Protozoa of structures
which are neural in function, it was thought advisable to undertake
the task of which this paper is an account.
412 University of California l'iilili<-iiiit>nx in Znnlni/tj [VOL. 19
During the winter of 1916-17 when Dr. Yocom had found and was
studying the fihrillar system in Eitplotes patella, it seemed to me that
the experimental method of microdissection might be successfully
employed to aid in determining the actual function of this system
and that Yocom 's excellent morphological studies might be supple-
mented by experimental evidence.
The value and necessity of experimentation wa.s duly recognized by
Dr. Yocom, who has already added several experiments of another
sort to this essential phase of the problem. "In studying Euplotes
patella" (Yocom, 1918, p. 363) "that have been treated with very
weak solutions of certain ahemicals, such as neutral red. methylene
blue and especially nicotine, it ha.s been noticed that the anal cirri and
cytostomal membranellcs are the last to cease moving. The other
cirri become quiet but the membranelles and anal cirri have been
seen to move even after the cytoplasm lias begun to break up. Such
phenomena favor very strongly the idea that the motorium .serves as
a coordinating center between the anal cirri and the cytostomal mem-
branelles. However, other observations on living animals give even
stronger evidence in favor of the neural function. It has also been
noted in specimens subjected to a very weak solution of nicotine that
the frontal, ventral and marginal cirri continue moving even after the
animal has ceased to swim about. The membranelles also move but
more slowly than in normal animals. Occasionally one or more of the
anal cirri may be seen to make a feeble movement not sufficiently
strong to cause the animal to move. However, as the animal revives
from the effects of the narcotic and begins to swim about by vigorous
kicks of the anal cirri, a decided increase, in the rate of movement of
the membranelles may be noticed."
ACKNOWLEDGMENTS
This experimental investigation has been made under the very
helpful direction of Professor Charles A. Kofoid, whose kindly and
stimulating criticisms have contributed much to any merits the results
may possess.
My thanks are also due to Professor S. S. Maxwell for several
valuable suggestions on methods and useful literature.
Tdfilur: .\iiiriiiiiiifnr A if/i/init us in l^ii/i/nh x 41H
.MKTIIOD AND .MAT KIM A I,
Tin- method of microdissection has been greatly improved with the
use ..!' glass needles manipulated in a three-movement holder intro-
din-cd several years ago liy Dr. .M. A. I'.arher and later extensively
employed In Kite and ( 'hamb. rs (1!)1l_M. Kite 1!M:!,/ and &), Cham-
bers f1!H4. 1!)1.">. 1017. b. and 1!I1S) and Seifri/ (1918). Tlic
technique used liy these investigators makes possible the dissection
and observation of ova. spennato/.oa. fresh tissues and Protozoa under
the highest magnification of the microscope. A detailed description
of the method is -riven by Barber (10141 which has been elaborated
by Chambers i 1H1.~>. 101*>. T have made use of the principal features
of this method in these studies on Kit/iluto; jiniillii,
The efficiency of the liarber instrument is indeed remarkable. Con-
siderable experience was found necessary for drawing the finer and
m"st serviceable needles, but their manipulation in the three-movement
holder is a comparatively simple matter. One learns the adjustment
of the screws controlling the needle almost as readily as the operation
of a mechanical sta-re. After some practice the facility with which
the apparatus may be manipulated and the feats thus made possible
with a pi ass needle arc rather surprising.
Mnixl i Itimilii rs. Two forms of moist chambers have been success-
fully employed. A Mausch and Lomb monocular microscope havin.-r a
rotary staire was first used. For this stali<-i/x in Zoology [VOL. 19
above (p. 415) illustrate four forms of shanks which were found most
serviceable. For convenience 1 have named these: a, right angled; b,
acute angled; c, obtuse angled, and tl, V-shaped shanks. NYcdles a
and b have been used for probing or tearing regions or dissecting off
parts; needles c and d for making incisions and, particularly <1, for
bisecting the organism, making wide incisions or snipping off organ-
elles. The V-shaped shank affords more flexibility, which may be
increased by lengthening the V.
Control. To provide for the control of the organism during opera-
tion, several methods were tried. Fine fibers of silk and of cotton,
also very finely ground particles of glass were sealed with agar to the
surface of the cover-slip. These afford helpful means of holding the
animal in place for the beginner until he lias learned the rather diffi-
cult but by far the most satisfactory method of control, namely, water-
glass surface tension, suggested by Kite (1913, p. 146). I have used
a very small pipette with a rubber tube attached for the mouth as a
means of transferring the animals and reducing the volume of the
hanging drop to afford just the necessary amount of surface tension.
This amount one learns only after considerable practice. Allowing
slight degrees of evaporation also facilitated this proper adjustment.
The animal must -be held in place but a further increase in surface
tension may cause it to disintegrate, often with explosive violence. A
perfectly clean surface of the cover-slip and a wide hanging drop,
say 10 mm. in diameter, aid greatly in obtaining proper surface ten-
sion. Another fairly satisfactory and more simple method of control
is to confine the protozoan within a very small hanging drop, the
surface tension of which with the glass is greatly reduced by applying
a mere trace of paraffin or some other harmless oil.
In making an incision, the needle was applied suddenly and rather
firmly by means of the up-and-down movement screw. After an
interval of a few seconds, this screw was slowly turned back and forth,
which caused a seesaw movement of the needle-point. With proper
care and if the needle be not too flexible, a surprisingly clean cut may
thus be .made without any loss of endoplasm. Chambers (1917a) has
very helpfully suggested the use of a needle not exceedingly fine and
the importance of slow movement and sufficient time in making an
incision. Otherwise a loss of endoplasm usually results and this may
be followed by rapid and complete disintegration. This outflow of
endoplasm may, however, be regulated to advantage by applying a
V-shaped needle near an animal in which a careful incision has been
Tr: \i iiriiiiii'lur .\ i>i>nnit HX in l-'ii jilutt s 417
made and which is held near the eduv of ;i wide but very shallow
hanging drop. Hy slowly turning Ilie screw I'm- the up-and-down
movement, delicate changes in the decree of stress of the surface film
are thus effected, an outflow of endoplasm may he indu I and its rate
of discharge varied more or less at will. As will later he described,
this atl'urds a study of several interesting features including the nature
anil extent of the ectoplasm and of the pellicle.
S/niiiiiii/. --Several vital stains have been employed with varying
success. For the study of the external organdies, a .0001 per cent
solution of haematoxylin gave the most satisfying results. This was also
useful in staining the fibrillar system; certain new features of this
system, in fact, were first seen after the animals had been subjected
for about eighteen hours to this stain. Tt was incidentally discovered
that a very weak solution (.001 -.0001 per cent) of tannic acid, after
eight to ten hours, distinctly sharpens the outline of the fibrillar
apparatus. This is apparently due rather to its effect upon the cyto-
plasm, affording a contrast which discloses more clearly the apparatus.
Neutral red (Griibler). new methyleiie blue R (C. C. Co.), toluidin blue
(iriibler) are among other vital dyes which enhanced the view of the
system of fibers. Usually for dissecting, however, the anal cirri fibers
and not infrequently the motorium with its attached fibers, may he
seen clearly enough under oil immersion (2 mm. Zeiss apochromat),
without the aid of intra vitum dyes.
For studying specimens fixed and stained before or after dissection,
the several fixatives and stains employed by Yocom (1918, p. 342) were
used with good results. The method of picromercuric fixation followed
with Mallorv's stain or with iron-haematoxylin was especially valuable
for the study of the fibers before and after they were cut. Delafield's
haematoxylin stains the fibrillar apparatus even more distinctly. There
was some evidence that the cut fibers do not stain so deeply with the
iron-haematoxylin. but this has not. as yet. been definitely ascertained.
-Much care is necessary in staining single specimens. Fixatives were
applied, usually hot, by means of the pipette (above referred to) under
tlie low power binocular. The specimen was then transferred to a
cover-slip or slide which had been treated with Meyers albumen fixa-
tive. After a distinct film had formed, the slide was passed through
the alcohols and stains, visually without detachment and loss of the
specimen.
Material. The fresh water ciliate. Euplotcs patella, possesses cer-
tain morphological features that make it an unusually choice subject
418 I' nil < rxih/ of California Publications in Zoology [Voi.. 19
for microdissection studies. Plate 29, fig. 1, illustrates several struc-
tures which are very favorable for operative work on the neuromotor
apparatus. The large C-shaped nucleus permits the cutting of the anal
cirri at several points with no injury to the nucleus. Also, the cyto-
stomal fiber may be cut at various angles and the motorium destroyed
likewise without injuring the nucleus. The stiff, fairly tough pellicle
which envelops the body ably maintains the normal form after an
incision, often very deep, has been made. The remarkable firmness of
this structure makes possible the removal of cirri with no apparent
injury to the body. The projection of the oral lip and of several cirri
affords successful excision of these parts, and the definite grouping of
the frontal, ventral, anal, and marginal cirri permits various transee-
tions and combinations of transections and excisions that have proven
to be exceedingly useful in studying the functions of these groups of
organelles in creeping and swimming movements. The location of the
single micronucleus at the anterior end of the body is especially favor-
able for ascertaining more accurately the specific role of this interest-
ing and important organ.
THE LIVING ORGANISM
Owing to the invaluable aid of water-glass surface tension for the
control of Protozoa in a hanging drop, it is now possible to study
active, living organisms in minute detail under the highest magnifica-
tion. With a properly constructed moist chamber, the time limit for
this study depends rather upon the endurance of the observer. A
living Euplotes was held continuously within the field of a 2 mm. Zeiss
apochromat lens for more than two hours, at the end of which time,
when a drop of water was added, the animal swam slowly about ;
within half an hour its movements were apparently normal. This
allotment of time is ample for a complete, detailed review of all the
structures and movements of the organism that may appear within the
range of microscopical vision. By properly adjusted, transmitted light,
the binocular microscope with an apochromat lens affords here the view
of a living, active form that rivals any of nature's finest displays. The
study of living organisms always lends increased interest and adds the
essential complement to our knowledge of the structures and relations
disclosed in fixed material.
Timlin-: Neuromotor Apparatus in Kiln/is 410
ENDOPLASM
In his microdisaection studies on living ova of certain marine
invertebrates. Chambers il!tl7> finds their cytoplasm to consist of
"a hyaline fluid matrix in which arc imhcddcd granules of various
sizes." The granules, classified into microsomcs and macrosomcs.
differ considcralily not only in size but also in number, shape, solu-
bility, refractive indices and in chemical reactions. Rapid tearing of
the internal cytoplasm with the needle induced in that region the dis-
solution of the macrosomee and liquefaction of the cytoplasm in which
the niicrosonics exhibited distinct I'.rownian movements. Such injuries
sometimes spread throughout the entire cell. Also. a. rapid dissolution
of the macrosomes occurred 'with the outflow of the cytoplasm into the
sea-water "if no protective membrane intervened." The microsomes
were much more resistant and displayed the dancing Brownian move-
ment for a considerable time after the complete disappearance of the
liquefied cytoplasm. A protective membrane frequently formed around
a mechanically injured, disorgaiii/ed area within the cell or on the
surface of endoplasm exuding through a rupture of the surface-film
or ectoplasm. This membrane is directly comparable with the ecto-
plasm. Both represent a colloidal gel enclosing the endoplasm which
usually exists in the sol state but may come to form temporary organs
such as the cell asters (Chambers. 1917ft) by a reversal of the sol to
the gel state.
A similar consistency of cytoplasm can be identified in Euplotes
lifi/ilnlix. ,-.< .. cut end: <;/ crtoplasmic granules; mac.,
niiicronurleus; HH'C.. micronucleus; n.p., nci'illc point.
irelatinoiis. rather rigid struoture composed of small granules imbedded
in a viscous, hyaline matrix (text fig. B). The organ is enveloped by
a very thin, structureless membrane. 1'pon exposure to the water, the
macronudeus increases slowly in size; within hall' an hour or so small
blisters of the membrane slowly appear over the surface; the rate and
extent of swelling increases and. upon rupture of the membrane in one
or several places, there follows a rapid dissolution of all except the
small granules, which for several hours exhibit a dancing Hrownian
movement. These granules vary somewhat in size, with an average
diameter about one fourth that of the microsomes found in the
endoplasm.
422 Unirtrsili/ of ('nlifuniin I'lili/ii-nHmiM in Zl/is 4i':!
The discharge of the vaciiole is clearly on the ventral side within
three or four microns of the right margin of the pellicle. This may he
observed with careful focusing when small food vacimles are lying just
posterior to the point of discharge. The relative position of the last
trace of a systole, as compared with that of the food particles and
ventral pellicle, appears distinctly ventral. Also, this position may he
verified by applying the needle-point very lightly against the ventral
surface near the point of discharge, whereupon the position of the
discharge is ventral.
ANAL A PERT IT BE
. This has heen located in E. ixitflla on the ventral side slightly
posterior to the discharge pore of the contractile vaciiole and within
five microns of the margin of the pellicle. It was first observed when
two i'rustules of \/i<j |\"oi,. i'.
mierodissection experiments, I should subdivide the seven frontiil cirri
into an anterior group of three and a more posterior group ' t'our.
Accordingly, these will liereinafter be referred to as the "group of
three" and the "group of four" frontal cirri.
The ciliary composition of the cirri of various Kiipltihs is a well
established fact. The component cilia with their basal granules have
been described for the cirri of E. nnnnix by .Minkiewiez (1901}. of
E. Jiarpa by Prowazek (1902), of E. worcegteri by (Jriffin (1910). and
of E. patella by Yocom (1918). This feature of a cirrus may be
readily demonstrated in a shallow hanging drop by means of a V-
shaped dissection needle. Here a del ached cirrus may be pushed to
the edge of the hanging drop for greater surface tension and gently
rolled to and fro between the needle and cover-slip. Soon the cirrus
splits into loose bundles of its numerous cilia. But this method reveals
other features: the cilia are embedded in a gelatinous matrix that is
highly viscous, as may be seen by pushing the bundles about with the
needle. These remain attached at one or several places even after
rather rough handling. They frequently adhere to the needle and so
may be pulled a considerable distance through the water. Upon ex-
posure to the water for a few minutes, the cilia of the bundles further
separate and show adhering to their sides minute globules of the
coagulated matrix. The question here arises whether this coagulation
of the viscous, hyaline matrix may not account for the extreme rigidity
that overtakes the cirrus soon after its detachment, when it may be
pushed about and even beyond the margin of the shallow hanging
drop without any apparent bending. Furthermore, after examining
numbers of these cirri by the above method, one becomes rather con-
vinced that the matrix-eilia complex is invested with an extremely
thin, structureless membrane that is fairly tough but very flexible. I
have not been fully satisfied about this structure since I have not
clearly seen it apart from its enclosure. This final evidence may later
appear. However, if present, the membrane rapidly dissolves from a
recently detached cirrus, which then splits into its component cilia.
Except the anal cirri, all are round at their base and gently taper
to a rather sharp point. The two right marginal cirri are fimbriated
(Yocom, 1918). Not infrequently the second and third (numbering
from left to right) anal cirri are also fiinbriated. The shape of the
base of the anal cirri differs considerably from the others. Figures
19 and 18 show the comparative dorso-ventral width and lateral thick-
ness of an anal cirrus base, the former being six to eight microns and
the latter about three microns.
Tui/lnr: \< in-i'iiiiit'ir .\i>inu-
The jitt;icliinciit ill' the cirri will he discussed in connection with a
description of the nclinunotor ;i|)|>a fill us. It remains here to describe
lirielly tlie several movements that are common to the different groups
of cirri. I'iitter i 1!iu:!i discusses these general types of ciliary move-
ments aiming I'roto/oa: (1) tlie "hook-like" type. found in cilia or
tlagella used for food-taking: ( 1' i the "whip-like" type, exemplified
I'.v the tlagellum of Kiii/hita. and 3) the " int'undihular or funnel-
like" type, very common among most flagellates and ciliates. The anal
cirri of H. /nitiHii frequently exemplify types hot h I i and 2), while
t\ pes 1' i and (3) are common for their frontal, ventral, and marginal
cirri. Yoeom'a observation 1M1S. p. :!(i:5i. that the anal cirri "move
in only one plane, that parallel to the median plane of the body." is
hardly adequate. As will he described presently, these cirri arc very
frequently used in guiding tlie animal to the right or left, and are
' s| ially active as the chief means for making sharp turns to the
right, which is not an uncommon reaction during swimming. In the
latter instance, part ieularly cirri .'!. 4. and ."> ( numbering from left to
righO are flexed rather abruptly near their base and lash close along
the ventral surface of the body. (iritTin C1910. p. :!(!) regarded the
anal cirri of K. Worcester* to have "only a single, strong motion: a
vigorous kick directed backwards. " Tn K. jinhUn, however, this back-
ward stroke is by no means the only effective movement, nor even the
most important. The "avoiding reaction" of this species, which will
be described further on. is effected chiefly by means of the anal cirri.
Furthermore, these cirri, together with the frontal and ventral groups,
are the animal's "feet" for creeping and. as we shall see later, upon
removing the anal cirri, creeping becomes impossible.
Another common use of these anal cirri may be observed in their
attachment to suspended debris in the water and swimming about with
it sometimes for several minutes; or. less frei|uently, in holding on to
floating debris or even to the dissecting needle and suspending the bodv
dorsal side down, occasionally at an angle of fifteen degrees or more.
The attachment, to the needle at least, is usually with two or three ami
often four anal cirri. Tn such cases I have observed clearly a slight
flexure of the tip of one or more cirri about the needle and had con-
cluded this to be the means of supporting the body; but later, an
attachment by only one cirrus was seen with the tip several microns
in length lying along the under side of the needle. This latter obser-
vation has since been made a number of times and in two instances I
was able to move the needle slowly back and forth without disturbing
426 University of California Publications in Zoology [VOL. 19
the animal, when the support was sufficient to carry the body along
with the needle. As to how this curious feat may be accomplished I
can only conjecture the possibility of a secretion present on the cirrus.
MEMBRANELLES
Projecting anteriorly from along the dorsal base of the oral lip, the
series of membranelles turn ventrad on the left in a gracefully twisting
curve and continue along the left side of the cytostome and pharynx
to end in a hooklike turn at the apex of the pharynx. Yocom (1918,
p. 4) has aptly likened the twisting and general shape of this con-
tinuous series to the collar and lapel of a coat. His splendid detailed
description may be referred to for the more minute structure of these
organelles. A further description concerning only their attachment
and their relation to the neuromotor apparatus will be given later
under the heading "Experimental." However, the considerable dis-
cussion on the actual relations of the cilia which compose the mem-
brancllcs described for various Euplotcs is here worthy of note.
Obviously, these relations condition the shape of the membranelles.
For E. harpa, Wallengren (1901) describes and figures the mem-
branelles as triangular in shape. Minkiewiez (1901) found those of
E. vannws to be of a similar shape. Yocom 's discussion of this point
would seem to favor the view of the above authors, although he does
not refer to the particular shape of a membranelle. Griffin (1910a),
on the other hand, states that after repeated examination of these
structures in E. worccsteri, he is inclined to believe that the mem-
branelles which are nearly rectangular in shape are composed of dis-
tinct cilia ' ' with movements so perfectly coordinated that they act and
ordinarily appear as a single and delicate band" (p. 299). Mobius
(1887) had come to the same conclusions regarding both the shape and
structure of the membranelles of E. harpa.
Prom the present studies on E. patella, I am convinced that the
cilia composing a membranelle in this species are definitely fused and
that they are so arranged as to give each membranelle the shape of an
elongated triangle. Indeed, those extending over the oral lip (fig. 16)
approximate the form of a short cirrus with a very wide base. By
means of a dissecting needle, several of those dorsal to the oral lip
may be excised, together with a portion of that organ from which they
readily separate, and thus the features mentioned above may be
exhibited. They may very soon split into bundles of component cilia
Tiitilnr: Neuromotor Apparatus in /.'/>//<. < 427
that show basal granules distinctly, while later there appear along the
cilia minute, coagulated globules comparable witli thus.' described for
the cirri. Also, excellent views of the shape and arrangement of the
entire series of membranclles may be had upon transferring an
organism to a hantrintr drop of 0.1 per cent solution of tannie acid. The
animal usually dies within a few minutes but in the meantime the
inembranelles become stained and their movements are slowed so as
to afford a splendid study of each membranelle of the entire series.
The primary function of the mcmbranclles of the cytostomal and
pharyngeal region is food-taking. Yoeom (1918) has discussed the
manner of the intake of food, but he does not refer to the expulsion
of particles from the pharynx after they have been "sampled" and
refused. This ejection may be sometimes rather violent and is effected
by a reversal of the membranelles which may involve only those of
the pharynx, or also the cytostomal nu mbranelles. or occasionally
even the entire series. The chief function of the adoral membranelles
is their indispensable service in swimming:. An acount of this im-
portant feature is given in later paragraphs.
XKCROMOTOR APPAKATI-S
The system of fibers connecting the series of membranelles. the
lattice-work structure of the oral lip and the five anal cirri to a small
bilobed body lying in the extreme anterior right of the animal, together
with other fibers radiating from the base of the remaining thirteen
cirri were found and described by Yocom (1918) as the neuromotor
apparatus of Euplnti s patella. In preceding paragraphs I have given a
brief but fairly complete review of Dr. Yocom's account of this appa-
ratus. It is my purpose here to reconsider certain parts of his account
and in following paragraphs (see "Experimental") offer a few minor
modifications and additions (fig. 13).
Following Yocom's figures and descriptions, I have been able to
identify in the living organism all the structures of this interesting
and complex mechanism. The anal cirri fibers are usually distinctly
visible throughout most of their length. The presence of food vacuoles
dorsal to the frontal cirri frequently interferes with the tracing of
these fibers to their junction with the motorium, but this interference
may be obviated by keeping the animals in well-filtered water for
several hours, at the end of which time most of the food vacuoles will
have disappeared. It is then possible to observe not only all five fibers
428 I' nii'frxili/ of California 1'ti/ilications in Zoology [ VOL. 19
throughout their extent but also the motorium and from its outer end
the membranelle fiber passing to the oral lip and membranelles. After
they are once clearly identified with the aid of vital dyes, the motorium
and its connecting fibers may be recognized usually with little difficulty
in unstained animals.
The several fibers associated with the base of the frontal, ventral,
and marginal cirri are much less distinctly visible. Very careful
focussing and regulation of light are necessary, and even then it is
usually impossible to make sure of these fibers without the aid of vital
dyes. This may be said also of the membranelle fiber along the base
of the membranelles. Here the presence of the basal corpuscles of the
cilia composing the membranelles and of a compact row of large ecto-
plasmic granules (fig. 17) renders this fiber so obscure that a distinct
and satisfactory view of it may be had only after dissecting off the
membranelles and oral lip and allowing the ectoplasm to disintegrate.
Most of the lattice-work complex within the oral lip may be distinctly
seen in ventral view. The basal attachments of this to the mem-
branelle fiber are indistinct if at all visible, due to the basal corpuscles
and large granules of the ectoplasm.
MOVEMENTS
So far as I have been able to ascertain, the creeping and swimming
movements of the genus Euplotes have not been described. In this
species, Euplotes pa-tella, there are evident three specific creeping and
six swimming movements. Of the latter, two are much less common
than are the other four.
Being typically of creeping habit, this animal is usually found
moving about on the bottom of an aquarium or over various debris and
vegetation or on the under-surface of scum or of the surface film of
the water. Its creeping movements, therefore, are readily observable.
This method of locomotion is effected by means of all the cirri on the
ventral surface, aided more or less by the ever active membranelles.
The three kinds of creeping movements are: (1) locomotion straight
ahead or slightly to the left (orally), (2) a quick, backward movement,
usually for a distance about equivalent to the length of the body, or less,
and (3) a turn to the right (aborally) through an angle of thirty to sixty
degrees. Movements 2 and 3 are comparable with Jennings' "avoid-
ing reaction." The accomplishment of movement 2 probably involves
Tui/lar: \i iir<>iiii>) a sharp turn to the right,
similar to creeping movement (3), and (6) movement directly back-
wards, comparable with creeping movement (2).
It will be convenient here to recall the special, effective strokes of
the membranelles and of the various groups of cirri : (a) The elTeetive
strokes of the membranelles may pull the animal forward or by reversal
drive it backward. Without the interplay of cirri, the limli /lltcs patdln. Of those experiments. Ml") weiv recorded
with fairly extensive notes mi the exact location and nature of the cut
and on the animal's reactions before, during, and after the operation,
allowing several minutes for its recovery from the shock effects. The
various cuts include: (1) 1 ransoctions i dividing the animal in any
piano at right angles to its long axisK i iM excisions of external
organelles with or without a portion of the body, and i'8) incisions in
the liody or oral lip in any plane. Efforts were made also to ascertain
some of the physical properties of the pellicle and of the librillar
system.
PELLICLE
This membrane which completely envelops the body and oral lip of
Kiil>lnttx ixilillii is firm, fairly tough, and sufficiently rigid to main-
tain constantly the normal form of the body and lip. even when the
animal is subjected to a considerable stress from changes in water-glass
surface tension or to the applied pressure of a flexible needle. Figure 1
shows tlie extent of an incision fully two-thirds the width of the body,
yet this animal continually kept its normal shape during a half-hour
of devious movements through the water. In making dissections the
toughness of the pellicle requires the use of needles with rather stiff,
short points. Long-pointed, very flexible needles are ineffective.
The extensile property of the pellicle is quite obvious in an animal
which has gorged itself with food until the body is conspicuously
bulged. If such an animal be subjected to a gradually increasing
pressure by the surface tension method previously described, just
sufficient to cause the egestion of a few food particles through the
pharynx, then as the needle is slowly removed the pellicle may here
and there become wavy or wrinkled. "Within a few minutes the
wrinkles usually entirely disappear. The elasticity of the membrane
may be readily demonstrated by applying a fairly flexible needle the
full width of the body when, with due pressure there occurs a con-
spicuous bending of the body over the needle. Upon releasing the
pressure the body at once resumes its normal shape. This may be
repeated successively many times. If. however, the animal has been
432 University of California l'ii/i/irations in Zoology [VOL. l
well flattened out by surface tension for about an hour, the flatness
persists for a time after a drop of water has been added, but gradually
the body recovers its normal form, usually within half an hour or less.
During an incision, short furrows frequently appear on either side of
the needle (fig.l). These may remain for some time but eventually
disappear.
Any apparent modification in the shape of Euplotes patella occurs
only from extraneous pressure.' That the animal of itself is unable to
vary its shape may be observed when it is hemmed in by cotton or silk
fibers partially sealed to the cover-slip. Paramecia in the same hang-
ing drop force their way among the fibers through narrow passes with
constrictions of the body, a feat quite impossible to E. patella. Further
contrast in the pellicles of these two forms is seen upon adding a weak
solution (.1 per cent) of tannic or acetic acid. "Blisters" quickly
appear on Paramecium but not on E. patella, although both may die in
the solution within a few minutes.
FIBRILLAR SYSTEM
Studies of the fibers and their relations were made by means of
various dissections but the most satisfactory observations were had
when a slow disintegration of the body was brought about by inducing
delicate changes of surface tension with a V-shaped needle. There-
upon the fibrillar system and its attached organelles would often
remain intact and were always the last part of the body to undergo
disintegration.
The anal cirri fibers normally lie upon the inner surface of the
ectoplasm just above ventral grooves which are formed by clcarly
defined ridges. Each ridge is chiefly composed of a single row of very
large ectoplasmic granules (fig. 20) that at times present internally a
finely granular appearance and often persist several minutes after
the body has entirely disintegrated. Sometimes they have been seen
to swell and burst explosively, disappearing entirely from view. These
and surrounding smaller ectoplasmic granules lie embedded in a
hyaline, gel matrix which apparently is continuous with the basal
plates of the anal cirri. This region of ectoplasm resists disruption
longer than the adjacent portions and so it frequently happens that
the anal cirri fibers, which lie upon the inner surface of the ectoplasm,
all remain intact after the complete disintegration of the body. This
condition, however, does not long prevail. Soon the ectoplasm here
1920] Tai/lur: Newromotor Apparatus in KI<>II x 4:i:!
S!HI\\S signs of dissolution by a gradual dispersion of its granules and
llii' anal cirri libers, with or without their cirri attached, atv at length
set free, tlicir spatial relations occasionally remaining unchanged.
Can- fill observations during tliis tardy disintegration of cctoplasui,
aloni: with tlie explorations by means of the needle, make it. fairly cer-
tain that the anal cirri fibers do not lie within the ectoplasm but upon
its inner surface, being supported there by a very thin, hyaloplasmic
sheath which may be a continuation of or comparable with the hyalo-
plasmic matrix in which are embedded the granules of the ectoplasm.
The critical focus for a fiber does not appear to be identical with that
for the ectoplasmic granules along (below) the fiber. Furthermore,
(lie fillers are more or less readily displaced by means of the needle,
although when undisturbed they remain adherent to the ectoplasm.
When set free from all attachments, the anal cirri fibers may be
bent variously with the needle (fig. 15). They are then found to be
fairly flexible, in no wise brittle and almost wholly irresilient. How-
ever. In-fore the ectoplasm has completely dissolved, the fibers are
much less flexible and generally recover after being bent. Figures 14
and 15 illustrate several permanent shapes into which the fibers were
bent by means of the needle. They may adhere to the needle and so
be pulled about through the water. They do not long resist dissolution
and so disappear usually within fifteen minutes or less time after their
exposure to the water.
Apposed dorsally to the basal plate of each anal cirrus, the corre-
sponding fiber is modified into a "fan shaped structure' (Yocom, 1918)
which I shall here designate the "anal fiber plate." This small plate is
distinctly rectangular (fig. 14), and not oval as figured by Yocom. Its
attachment to the fiber proper is secure, as may be readily ascertained
by pulling or pushing the fiber about through the water with the
needle-point. An interesting and significant feature is its intimate
association with the basal plate of the anal cirrus. Figure 14 is a
camera drawing of a cirrus in the process of detachment from the
"anal fiber plate." It will be observed that the cirrus has rotated
90 degrees on its long axis and that the gelatinous extensile basal plate,
which is a highly viscous gel, remains attached to the anal fiber plate.
This attached condition is rarely found, owing to the readiness with
which the basal plate detaches from the anal fiber plate. While
attempting to make this drawing with the parts in situ, the separation
ensued so readily that I succeeded in outlining only the partial detach-
ment as shown in the figure.
434 Unifcrnihj of California Publications in Zoology [VOL. 19
Just as the anal cirri with their attached fibers frequently persist
intact after the remaining cytoplasm has dissolved, so also do the mem-
branelles with the membranelle fiber resist immediate disintegration.
Furthermore, in seven recorded instances I have observed the anal
cirri, their fibers, the motorium, the membranelle fiber, and the nn 111-
branelles, all remain united for several seconds to about three minutes
after the disruption of the body. In three of these cases, the anal cirri
and membranelles continued lashing, but feebly and for a few seconds
only.
The motorium with its attached jiirmbnnielle and anal cirri fibers
has been distinctly identified after more or less complete disintegration
of the body. Much more frequently, however, only the fibers are
evident. It would appear, therefore, that the motorium readily
detaches itself from its connected fibers or otherwise vanishes, perhaps
by rapid dissolution. In its normal position the motorium may be
readily displaced with the needle-point. However, it resumes its usual
position upon the removal of the needle. But if it be pushed too far,
say ten microns, out of place it may become detached from its fibers,
or apparently injured to such an extent that it dissolves or otherwise
disappears.
In unstained animals, as stated previously, the membranelle fiber
may be distinctly seen only a short way from its attachment to the
motorium. Thereafter it becomes concealed among the ectoplasmic
granules along the basal plates of the membranelles (fig. 17). It may
be observed only after these granules have dispersed with the dissolu-
tion of the ectoplasm. Its general physical properties are apparently
the same as those above stated for the anal cirri fibers. That descrip-
tion may suffice for this fiber also.
However, associated with the membranelle fiber and membranelles,
certain plates have been found which I shall here call the "mem-
branelle fiber plates" (fig. 13). These were first clearly observed upon
partial disintegration of the series of membranelles which had been
dissected from an animal vitally stained for about eighteen hours in
a .0001 per cent aqueous solution of haemotoxylin. The membranelles
proper had been set free, thus exposing these plates, one for each
double row of membranelles. Figure 17 is a camera drawing of the
plates and the membranelle fiber. The spokelike formation shown in
the figure is usually assumed by the series of plates upon detachment
of the membranelles and disintegration of the ectoplasm. This
arrangement is clearly occasioned by their individual attachment at
THI/IUI': Neufomotor Apparatus in Euplotes !!">
only OIK- cud to the membranelle tilicr. Explorations with Ilic needle
show this connection to be fairly secure. Also, the relation of each
niembranelle tn its corresponding membranelle liber plate has been
found to he the same as the relation of tin- anal cirrus to its anal fiber
plate. Of this one may he fully convinced upon observing the nicin-
branelle peel from it.s plate, a process which occurs not infrequently
about one minute after the disruption of the ectoplasm. Thereupon,
the basal plate of the membraiielle, in which the basal corpuscles of
the component cilia and the ciliary rootlets are imbedded, eompletely
sepai-ales from the membranelle fiber plate which, like the anal cirrus
plate, shows a smooth, clean surface, with no evidence of any ciliary
rootlets having been attached.
The "dissociated libers" described by Yocom (1IMS) as radiating
at the base of each of the thirteen cirri (i.e.. excluding the anal cirri).
have been found to be definitely connected with a plate somewhat
similar to the anal cirri plate, although of a shape (fig. 21) correspond-
ing to that of the base of the cirrus. These were first observed upon
the disintegration of an animal likewise .stained with a .0001 per cent
auctions solution of hacmatoxylin. Several radiating fibers were dis-
tinctly seen to be united to each plate. As yet. T have not definitely
observed the separation of one of these plates from its cirrus. Indica-
tions in two cases where the separation was almost complete point
toward a relation between cirrus and plate here that is similar to the
relation of an anal fiber plate to its corresponding cirrus. I shall
designate these plates the "dissociated fibers plates." Kiiru res 21 and
~2}/i show several such plates from the same organism which vary
slightly in sixe and shape. These variations are apparently common.
TRANSECTIONS
Hitirii n /In "i/rmij) itf tltr/i" and "i/rnup of ftiitr" frtnilnl rirri
i lig. 2). The anterior part of the animal swims rapidly (of. swim-
ming movement :i. p. 42!)). the inner side, that with the three frontal
cirri, performing a small circle and the opposite side a correspondingly
larger one. This performance continues the same after more water is
added to the hanging drop. The part infrequently revolves, as on the
IOULT axis of the normal animal, and it occasionally reverses the effect ivo
stroke of the membranelle.s to drive itself a short distance backwards
(cf. swimming movement 6, p. 429). In either case the circus move-
ment to the right is soon resumed and continues with few such inter-
ruptions until the part apparently becomes fatigued and dies. Death
436 University of California l'ul>Hc!ut/s 4:57
for long periods. Its oral lip is m<>iv sensitive to a stimulus by the
needle-point than are the membraiielles over the oral lip. or its pos-
terior. cut surface, or the frontal cirri or any other part.
The posterior part is generally very much less active. However, in
ten recorded instances this piece revolved on its cut surface as an axis
exceedingly rapidly i about two revolutions per second > for a half
minute or less just after the transect ion was completed. 'Phis revolv-
ing performance. generally at a much slower rate, is a common reaction
of the posterior piece following this operation. The direction of these
rexolutions is clockwise when viewed from the left side. For some
time after the cut is made the anal cirri are quite active with their
etl'cctive stroke in such a way as chiefly to induce the revolutions, '['his
part swims in circus movements to the right infrequently and very
seldom rotates on the long axis; when it does so, it moves quite
clumsily and imperfectly. Within about an hour movement ceases. It
is then much less responsive to mechanical stimuli than is the anterior
part, after coining to rest. When thus stimulated its movements, which
are for the most part revolutions, are effected chiefly by means of the
two ventral and the two right, fimbriated marginal cirri, the anal cirri
remaining more or less passive.
Experiment 209 (fig. 3). Anterior part swims violently in various devious
movements, sometimes rotating on the Ion;; axis or reversing to swim a short
distance backwards, but most of time it moves in right circus movements. This
r-casrlfss swimming continued from 11:50 A.M. until about 5 P.M., when its move-
ments were considerably slower, and at 5:30 P.M. the part was resting on debris.
Readily responded to touch of the needle point against the oral lip, but less so
when the adoral membranelles, frontal cirri or posterior cut surface was simi-
larly stimulated. Slight jarring induced violent swimming, which lasted about
thirty seconds, after which it again became quiet. At this time rotation on the
long axis was more common than previously. Following morning, this part bad
died.
Posterior part not very active from the first. Anal cirri beat slowly, irregu-
larly and with little effectiveness. Occasionally swam in circus movement to
the right and sometimes showed imperfect rotations on the long axis, but more
often its movements were revolutions about the cut surface as an axis. Within
forty minutes, it had become passive, the two right marginal cirri infrequently
showing movements which were always infundibular but without effect. Only
slightly responsive to jarring, then generally revolved as before but very few
times, after which it again became quite inactive. These revolutions were
effected mainly by the two right, fimbriated marginal cirri with infundibular
movement; the two on the left lashed with the effective stroke upward, thus
inducing the revolutions. The two ventral cirri were active most of the time,
also showing conspicuously the infundibular type of movement. The anal cirri,
on the other hand, were mostly inactive; irregularly one or two might lash
feebly, but never more than one at a time. Their effective stroke was always
backward, therefore tending to aid the part in its rotations clockwise as viewed
from the left. This part also died within about thirty-six hours.
438 University of California Publications in Zoology [VOL. 19
Between the two ventral a ml ju-c. anal cirri (fig. 4). Hero, the
movements of the anterior piece are quite similar to those of the same
part described just previously. There is, however, less tendency to
swim in circuits to the right .-mil spiral swimming movements are con-
siderably more frequent. Indeed, in the two respects just mentioned,
this part closely approximated the corresponding swimming movements
of the normal animal. There are, on the other hand, some notable
differences: (1) Avoiding reactions (swimming movement 6, p. 429)
are seldom observed even when the oral lip region is strongly stimu-
lated by means of the needle, or when some disagreeable solution, such
as methylene blue, is introduced. (2) Creeping is very infrequently
attempted and is conspicuously more or less impossible. In a few cases.
the piece has been observed to crawl slowly and awkwardly for a short
distance over-debris or along the needle, but this ability is distinctly
impaired. (3) Sharp turns to the right have not been seen. Tortuous,
random movements that involve turning both to the right and to the
left are sometimes resorted to but these are readily distinguishable
from the short, sharp turns to the right which are common for the
normal animal (swimming movement 5, p. 429). (4) The creeping
"avoiding reaction" (number 2, p. 429) has at no time been observed
even when mechanical stimuli are applied.
The principal characteristic movement of this posterior piece is its
rotating on the cut surface as an axis, a rotation which is not uncom-
monly very rapid (two or three times per second) following the com-
pletion of a transection. This performance is of brief duration and
the piece comes to rest on the surface film of the hanging drop or upon
debris. Thereafter, it is usually very irresponsive to mechanical or
chemical stimuli. If aroused, its revolving movements are performed
chiefly by means of the marginal cirri, the anal cirri functioning
individually and spasmodically, or not at all. But previously, just
after the operation, the anal cirri were very active and mostly respon-
sible for the rapid revolutions. Imperfect circus movements to the
right and aboral spiral movements are quite uncommon for this part.
These have never been observed after the marginal cirri were excised,
as a later experiment will show.
Experiment 160 (fig. 4). Anterior piece immediately swims in circus move-
ments to right, but as often or more often moves in aboral spiral straight ahead.
Sometimes performs winding, devious movements but returns to spiral swimming
or to circus movements. During ten minutes it reversed three times to swim a
short distance backwards; this reaction fairly normal. Two hours later, resting
on d4bris. Very responsive to jar, also to needle. Oral lip much more sensitive
than membranelles, cirri, or any part of the body. Slowly and awkwardly
Tiifilnr: Neuromot or Apparatus in Kit/ilo/ix 4:i'.i
\l a short di~; r debris. l>oes nut show creeping ' a\ oidinj;
tion" when stimulated with needle .]M>int or by means of methylene blue.
Also, :i|ijil'n>i| \\eak acetic acid, when part swain straight forward, then reversed
the effective stroke of orjianelles, swimming backwards a short distance, but
swain in circuit or in spiral apparently beyond tlie influence of the acid
solution.
Posterior part turned over and over very rapidly, two times per second, with
::rface as axis. This continued about twelve minutes. Slowed and came
to rest on Mirface til'" of han<.'inrni!ni/ii [VOL. 19
Removal of marginal cirri. These, due to their exposed position,
were readily snipped off with the needle. The excised parts thereafter
wire never observed to beat. But when one, two, three or all were
removed with some of the body plasm the cirri continued lashing very'
rapidly and driving the piece deviously through the water until death,
which followed a few minutes later. "When an excision (properly,
a transection) of the caudal end was made to include all four marginal
cirri, the piece revolved very rapidly with the cut surface as an
axis but in such manner as to move speedily through the water with
the left side foremost. Such removal or the snipping off of some
or all of these cirri did not apparently modify the several swimming
or creeping movements of the normal animal. If, however, these cirri
had been removed from an animal which was then transected just
anterior to the anal cirri, the posterior part usually rotated rapidly,
the cut surface as its axis, for several minutes. Circus or spiral
movements were at no time observed. But within an hour after
becoming quiet it was irresponsive to mechanical stimuli and did not
resort to rotating movements again. The anal cirri lashed feebly,
very irregularly and ineffectively.
Excision of frontal cirri. Owing to the length of these cirri and
the extension of four of them beyond the right lateral margin of the
body the four may be snipped off with a V-shaped needle. Thereafter,
the animal very seldom attempts creeping and its spiral movements
are abnormal. In the latter instance, its anterior end rotates in a
larger spiral than that of the posterior end. In two cases all but one
frontal cirrus were either snipped off or removed by inserting the
needle-point at the base of each cirrus, thus to gouge them loose. These
cirri came off rather readily. Three of them beat several times follow-
ing their detachment. In each case the animal could not creep, but
frequently swam slowly in circuits, or in spiral movements with the
anterior end describing spirals which were about twice the diameter
of those of the posterior end. No discernible injury resulted from
gouging out these cirri ; the movements of both the membranelles and
anal cirri were apparently normal. In a few instances, the animal
gave the avoiding reaction upon stimulation of the oral lip with the
needle-point, although these were feeble and abnormal. However, both
animals died within forty-eight hours without regenerating new frontal
cirri. Their death may have been due directly to injuries from the
excisions or indirectly to infections or other causes.
Excision of anal cirri. Infrequently, E. patella were found with
fully half of the anal cirri extending beyond the caudal margin of the
Ttiiiliir: Neuromotor Apparatus in l-'ii/iiiitis 111
liody. Ill several eases the anal cirri, to about two-thirds of their
length, tin' marginal cirri and a small piece of the caudal end of the
body were excised. Creeping was thus made practically impossible,
the animals resorted more frequently to circus movements to the right,
and sharp turns to the riirht were not evident. Spiral revolution on
the long axis was apparently normal. Four such animals regenerated
the excised parts, including the anal cirri.
Several attempts were made to ironic off the anal cirri just as the
frontal cirri had been removed. In two experiments ' nos l>1f> and
I'll!) all the anal cirri were successfully removed, with little or no
injury to the body. In each case, there followed several significant
results : (1) the animal was unable to creep. (2) it did not turn sharply
to the right. (3) the avoiding reaction was never observed, and (4)
circus movements to the right wore performed more frequently.
Experiment I'M'.. Kemoved anal i-irri 4 and ." (see p. ILM). Released the
animal by adding water to tin 1 hanging drop. It then performed all the major
swimming and creeping movements, including the avoiding reaction.
Again drew off tin 1 water and removed the remaining anal cirri. 1'pon adding
more water the animal was observed to revolve in spirals on the long axis and
to swim in circuits to the right, but at no time was it seen either to creep, to
turn sharply to the right, or to give the avoiding reaction. Its efforts to creep
on the under side of the cover-glass were unsuccessful, the posterior end being
suspended so as to incline the body at an angle of about 30 degrees with the
cover-slip.
INCISIONS
Tlii-mii/li lln nral lip ifitliout riittiiii/ Ike cytostomal fiber. There
was no apparent decrease in the sensitivity of any part of the oral lip.
and no change in the normal movements and functioning of the adoral
membranelles. The results were wholly negative. The cut usually
healed completely within an hour.
Through Ihe oral ///>. xri-iriiti/ tin i-iitoxlonuil fiber (fig. 5). Iri
seventeen cases there resulted abnormal swimming movements and
distinct changes in the movements of the niembranelles on either side
of the incision: (1) the progress of the animal forward was impeded,
(2) in its spiral revolutions, commonly the anterior end described a
wide spiral, (3) circus movements to the right were markedly less
common as was also (4) the occurrence of the avoiding reaction, and
."> periods of quiet were more frequent and of much longer duration.
I "pon examining with high power the movements of the memhranelles.
a difference in rhythm was frequently conspicuous between the series
on the left side of the cut and those on the right side. The former
442 University of California Publication* in /Wm/i/ [VOL. HI
were always active with that effective stroke which normally tends to
drive the animal forward. The membranelles on the right side of the
cut occasionally moved in coordination with the former or sometimes
did not move in the least but projected straight out from their bases.
Not infrequently, they were distinctly seen to beat with the effective
stroke in the opposite direction to that of the series on the left side of
the cut. Carmine granules or india ink which had been introduced
into the water clearly indicated these three changes in the behavior of
the adoral membranelles on the right side of the cut. It will be noted
that the membranelle fiber at the base of these membranelles on the
right side of the incision was continuous and in connection with the
motorium. These results of such experiments w r ere very obvious and
remarkably uniform.
Incision through the membranelle fiber at any point posterior to
the oral lip (fig. 6). Differences between the rhythm and direction of
the effective stroke of the membranelles anterior to the incision and
of those posterior were apparently identical with those just described
above. However, the swimming movements following such incisions
were practically normal. Some animals (three especially were noted)
were less active after the incision and showed more tendency toward
circus movements; otherwise, their swimming and creeping reactions
were comparatively normal.
Incisions on the right or left side or at the posterior end did mil
sever the cytostvmal fiber or any of the anal cirri fibers. Following
such incisions made in many animals at various angles through the
macronucleus or not (figs. 10-12) I have never as yet observed any
noteworthy change in their normal swimming or creeping reactions or
in the perfect coordination between the series of membranelles and the
anal cirri.
Incisions severing all the anal cirri fibers. Incisions were made
(1) on the right side between the group of three and the group of
four frontal cirri (fig. 7) ; (2) on the right side between the group of
four frontal cirri and the two ventral cirri (fig. 8) ; and (3) on the
right side between the two ventral cirri and the five anal cirri (fig. 9 1 ).
After severing the anal cirri fibers at any one of these three regions,
two significant changes were evident in creeping and three in swim-
ming movements: (1) there was distinctly less tendency to creep; the
animal when not swimming was more frequently found quiet on the
surface of the cover-slip, on the surface film of the hanging drop or
upon debris. But when creeping, the anal cirri were used with less
sureness and facility than normally. That much was commonly evident
'/'<;///iin>/nr A i>i>nit ux in Kiijilnl, \ 44")
of two different parts .Maier. 1903), an clastic axial lilaineiit covered
by a sheath which, according to Khainsky , 1!U(M. is continuous with
the pellicle. Kach ciliuin arises from a basal granule situatclntes
/;/l<>ttx 44it
None \vtmM question tlic evidence for a division of lalior among the
intracytoplasmie organelles in tins ciliate. and the several experiments
previously deserilied would indicate that the extraeytoplasmir organ-
elles. also, may share a decree of speeilie. but none the less coordinated,
functions in the animal's normal behavior. Accordingly, in accom-
plishing such swimming nioveinents as the sharp turn to the right or
the (|iiick backward, avoiding reaction, we may regard the anal cirri
as especially etl'ective if not normally indispensable, much as the large
caudal cirri in I'rcnii/cliin- arc largely responsible for that animal's
very rapid, backward movements (Calkins. 11)11. p. l 1 ^
In this consideration, it is important to note that the feature of
coordinated activity is in all respects evident in the normal K. /xitilln.
The claim here made is that the perfection of both creeping and swim-
ming movements is dependent upon the cooperation particularly of
those organdies (e.g.. the frontal and anal cirri in creeping) which
contribute most effectively to the performance of any usual movement.
Therefore, the elimination of any important group of organelles, or
the interference with any mechanism by which they operate or
cooperate with another similarly important group, should result in
perceptible changes in swimming or in creeping movements.
We may now enquire: Does the fibrillar system in Eui>1otes patella
re]) resent a mechanism that affects the external organelles individually?
Or does this complex, unified apparatus function in the coordination
of all the several groups of organelles with which it is intimately
associated? An affirmative reply to the first question would assign
either a supporting or a contractile function to this system, and to
affirm the second question is to attribute to the system the function of
conductivity.
The experimental evidences set forth in previous paragraphs sup-
port an affirmative answer to the second question, viz., that this fibrillar
apparatus exhibits features of conductivity functioning to coordinate
the groups of external organelles with which its unified and dissociated
parts are directly or indirectly intimately associated. These evidences,
furthermore, do not support the assumption that the system is either
contractile or supporting in function.
The facts which concern these three propositions may be stated as
follows :
Tin fibrillar system in E. patella is not skeletal or supporting in
function. The rigid, fairly tough pellicle is amply sufficient to main-
tain the normal shape of the body under considerable stress. It was
450 University of California Publications in Zoology [ VoL - 19
shown that the pressure of a very flexible needle when applied to the
full width of the body did not alter the normal shape of the animal.
Also, when the body was flattened for a few minutes by applying a
stiffer needle, or by surface tension, upon releasing the stress the body
at once recovered. It was also stated that the pellicle was sufficiently
tough to require in dissections the use of needles with fairly stiff, sharp
points. Other needles were ineffective. Furthermore, the firmness of
the pellicle is sufficient to preserve the normal shape of the body after
an incision fully two-thirds its width had been made. The friction of
water, induced by the animal's continuous and devious swimming
movements, effected no visible change in its shape. Any momentary
modification in the shape of E. patella can result only from extraneous
pressure. Unlike Paramoecium, which readily forces its way through
narrow meshes of silk fibers with distinct constrictions of the body, this
animal, owing to the consistency of its pellicle, is of itself unable to
alter its form.
The basal plate and not the fiber plate is the means of secure
attachment and support for both the cirri and the membranelles. The
rootlets of the component cilia of both membranelles and cirri are
imbedded in the gelatinous ectoplasmic basal plate and are only con-
tiguous with, but not attached to, the fiber plate. The readiness with
which the basal plate becomes detached from the fiber plate and the
want of any indications that the ciliary rootlets had been attached to
the smooth, clean fiber plate, was previously described.
The consistency, solubility, size, and shape of the fibers are incom-
patible with efficient structures for support. Particularly are the
anal cirri fibers frail, readily flexible, and irresilient. They may be
pulled in two or bent variously with the needle-point. When entirely
free from the ectoplasm they are not resilient and, by means of the
needle, they may be readily distorted. They may adhere to the needle
and thus be pulled about through the water. Their dissolution is
sometimes rapid and usually occurs within fifteen minutes or less
after being exposed to the water. It is probable that they are not
imbedded in the ectoplasm but lie upon its inner surface, being sup-
ported there by a thin, hyaloplasmic sheath. This loose attachment,
together with the extensive length and the minuteness of these fibers,
indicate that they do not function as supporting structures either for
the pellicle, which is of itself distinctly firm and resistant, or for the
cirri, whose component cilia are not attached to, but only contiguous
with, the basal plate.
1920] Taylor: Neuromotor Applnlcx 451
This fibrillar si/stim is not cnntrartili: in fit net inn. The contrac-
tility either of cirri or of membranelles is not conditioned upon their
attachment to the body and consequently not upon any mechanism
within the body. All the frontal, ventral marginal and anal cirri and
inembranelles have distinctly been observed to continue contractions
for a considerable period after their detachment from the body. These
reactions have already been discussed somewhat at length, and need
not be further elucidated here. It is now only worth while to empha-
size that their capacity of contraction inheres within these external
organelles themselves. Whether this contractility is effected by the
basal corpuscles, the axial filament of the component cilia, or the
plasmic sheath enclosing the filaments, is not for our consideration.
The loose attachment of the basal plate to the fiber plate indicates
that the fibrillar system differs both in structure and in function from
the contractile, external organelles. The ease and completeness with
which the basal plates become detached from the fiber plates and the
want of evidence that the ciliary rootlets and fiber plate are more
than merely contiguous structures are significant features supporting
this conclusion.
The consistency of the anal cirri fibers and their feeble attachment
to the ectoplasm and to the easily displaced motorium would suggest
their meager effectiveness in functioning as contractile structures.
The fibers tend to remain straight when undisturbed. They do not
become kinked or curled upon the disintegration of the ectoplasm. It
is only by means of the needle or some other external agency that they
may readily become distorted. They may be pulled in two with the
needle-point but at no time have they shown any indications of
stretching.
The reversibly effective strokes of the anal cirri preclude the possi-
bility that the anal cirri fibers are contractile in function. The four
effective strokes of these cirri have been described in foregoing para-
graphs. These are: (1) directly backward strokes parallel to the
sagittal plane, (2) directly forward strokes parallel to that plane,
(3) laterally backward strokes hardly parallel to the frontal plane,
and (4) similar lateral strokes directed forward. All these strokes
have been seen many times in the anal cirri of a transected posterior
piece as well as after an incision which had clearly severed the anal
cirri fibers. Since contractile fibers can operate effectively only in
one direction, it is inconceivable that an anal cirri fiber can function
as a contractile organelle.
452 University of California Publications in Zoology [VOL. 19
The fibrillar system in Euplotes patella does possess properties of
conductivity functioning to coordinate the movements of the external
organelles with which it is associated. Normal, coordinated activity of
the series of membranelles is effected through the motorium, the mem-
branelle fiber and its attached inrmbninelle plates. An incision at any
point through the oral lip, which did not sever the membranelle fiber,
gave negative results. But when the membranelle fiber was severed,
there were conspicuous changes in rhythmic movements of the mem-
branelles on either side of the incision and distinct modifications in
the animal's swimming movements. It was stated that the mem-
branelles on the right side, whose fiber remained connected with the
motorium, at times became inactive and projected straight out from
their base ; only occasionally were they seen to move in apparent
coordination with those on the left side of the incision. The latter,
the fiber of which had lost its connection with the motorium, showed
continuous movements with their effective stroke mostly such as
normally tends to drive the animal forward. This tendency in the
rate of movement and in the direction of the effective stroke is com-
parable with the unchanging, ceaseless movements of the adoral mem-
branelles of the excised oral lip which continually moved in circuits
to the right and was never observed to reverse the effective stroke of
the adoral membranelles. This constancy in the behavior of mem-
branelles whose fibrillar connection with the motorinm is severed might
suggest that their usual modifications in direction of stroke and rate
of movement may in some way be effected through the motorium. It
is furthermore evident that the unusual swimming movements which
followed such incisions resulted from the severing of the membranelle
fiber.
Efficient, coordinated behavior of the five anal cirri is effected
through the normal functioning of the five anal cirri fibers with their
attached fiber plates. The effects of severing these fibers at any one
of several regions (see Incisions, page 441, above) were distinct and
more or less constant. The infrequency and lack of facility in creep-
ing which was, at times, obviously initiated by the frontal cirri, and
the rare occurrence of the avoiding reaction were noteworthy changes
in the animal's creeping movements. But more evident were its
modifications in swimming. There was a marked tendency toward
performing circus movements to the right. Sharp turns to the right
were infrequent and in three cases at no time observed. The rapid,
backward, avoiding reaction has never been clearly identified after
Tii'tliir: If euromotor Apparatus in /.'/*//otes 455
nuclei" (Mim-hiii. 1912. p. 1). Metazoan organs arc composed of many
cells which liavc become modified and often highly specialized to form
tissues, of which several kinds may appear in the same organ. On
the other hand, organs of the Protozoa are not composed of cells but
are modifications of a single cell. We might, therefore, regard the
protoplasm within the organs of the protozoan as having the same
general physiological properties as the protoplasm throughout the
protozoan body and these general properties should be possessed in
common with those of any protoplasm wherever found.
Now one general property of all protoplasm is the propagation
throughout all its substance of an excitation effected by a stimulus.
The morphological continuity of this substance into all the parts or
organs of the protozoan body would appear to be the only essential
condition for the conduction of an excitation, wherever initiated, to
any such part or organ. If this condition is evident in all protozoans,
it would seem that specialized, conductive -structures for the trans-
mission of excitations were unessential and useless. Accordingly,
caution in ascribing a nervous function to a structure or a system of
structures in a protozoan body is justifiable.
However, may not as much be said for other general properties of
protoplasm? Chambers (1917a) has shown that the surface layer of
marine eggs may be pulled out into long strands "without otherwise
disturbing the contour of the cell. On being released the strands tend
to curl and retract slowly until they disappear" (p. 6). Similar
phenomena may be readily demonstrated in the endoplasmic globules
of E. patella that frequently form with the escape of the endoplasm
into the water. Also, the proverbial amoeba and many of its relatives
display the phenomenon of contractility in normal behavior, as do also
all amoeboid cells of the Metazoa. And the cytoplasm of amoebae
possesses no fibrils or other specialized structures, so far as is known.
by which it effects contraction. Nevertheless, this general property of
the cytoplasm is not functioned by such simple and primitive means
in many protozoans. It is a well-established fact that in the so-called
higher forms contractility is effected mainly, though perhaps not
exclusively, by specialized structures, the myonemes.
If, therefore, in the "unicellular" protozoan the general property
of contractility has become more or less localized in special organelles,
what should restrain conductive protoplasm from the specialization
of structures to facilitate conductivity? The extreme rapidity with
which many protozoans react to stimuli suggests the presence of
456 University of California l'n Mirations in Zoology [VOL. 19
specialized, conducting elements in their protoplasm. That such ele-
ments in the ciliate, Euplotes patella., have become unified into an
efficient, integrated system for the coordination of its associated
oganelles. is supported, it is believed, by experimental evidences set
forth in foregoing paragraphs.
Should further experimentation substantiate these results, then
their significance is clear. The most salient feature of stmelures and
functions in the Protozoa as in the Metazoa is not cellularity but
organization. The external organelles of a protozoan body are not
mere continuations of the protoplasm as the fingers are a part of the
glove. They are rather modifications which are sometimes distinctly
specialized, as the cirri and membranelles of E. patella clearly indi-
cate. Moreover, the complex, integrated fibrillar apparatus of this
organism signifies higher specialization in its intracytoplasmic struc-
tures. From these considerations it would follow that any general
conception of the Protozoa which assumes that any and all of this
extensive and diversified group of organisms are so simple and primi-
tive as to lack specific organization the specialization of intra- and
extracytoplasmic organelles is inadequate and will assuredly be
abandoned.
SUMMARY
The fibrillar system in Euplotes patella, found and described by
Yocom (1918) as a "neuromotor apparatus," has been identified in
the living organism both with and without the aid of vital dyes.
Other structures of this system not previously described are :
(a) membranelle fiber plates, each of which is contiguous with a mem-
branelle basal plate and is attached at one end to the membranelle fiber ;
(&) dissociated fiber plates contiguous with the basal plates of the
frontal, ventral and marginal cirri, to each of which are attached the
"dissociated fibers."
The rectangular anal fiber plates, a modification of the posterior
ends of the anal fibers, directly approximate the basal plates of the
anal cirri.
The fairly rigid pellicle is amply sufficient to maintain the normal
shape of Euplotes under considerable stress and after an incision fully
two-thirds the width of the bodv has been made.
1920] T was
seldom observed and (i was never seen after the fibers had been severed.
l>i ^friii/hiii lln iiinliii-iiiiii in- ciillini/ //\ iiHnrlnil flliii-ft inli rn/i>ts
coordination in tin iinin nn nix of tin adoral membranettes am/ anal
cirri.
Any incision not severing either the membranelle fiber or the anal
cirri fibers does not impair normal creeping or swimming movements.
These experimental evidences do not support the assumption that
the fibrillar system in Kuplotes patella is either contractile or support-
ing in function, but they indicate that this complex system of fibers
does possess conductive properties functioning in the coordination of
the movements of the locomotor organelles with which it is intimately
associated.
458 University of California Publications in Zoology [ VOL - 19
LITERATURE CITED
ALEXEIEFF, A.
1912. Sur la revision du genre Bodo Ehrg. Arch. f. Prot., 26, 413-19, 1 fig.
in text.
BARBER, M. A.
1914. The pipette method in the isolation of single microorganisms and in
the inoculation of substances into living cells. Philippine Jour.
Sci., 9, 307-58, 19 figs, in text.
BENDA, C.
1899. Weitere Mitteilung tiber die Mitochondrion. Arch. f. Anat. und
Physiol. (Phys. Abt.), Jahrg. 1900, 166-78.
BOECK, W. C.
1917. Mitosis in Giardia microti. Univ. Calif. Publ. Zool., 18, 1-26, pi. 1.
BRAUNE, E.
1913. Untersuchungen fiber die in Wiederkauermagen vorkommenden Pro-
tozoen. Arch. f. Prot. 32, 5-63, pis. 3-6.
BUTSCHLI, O.
1885. Einige Bemerkungen fiber gewisse Organisationsverhaltnisse der sog.
Cilioflagellaten und der Noctiluca. Morphol. Jahrb., 10, 529-77,
pis. 26-28, 4 figs, in text.
1889. Protozoa. Bronn's Klassen und Ordnungen des Thier-Eeichs., 1 (3),
1783-95.
CALKINS, G. N.
1911. Eegeneration and cell division in TJronychia. Jour. Exp. Zool., 10,
95-116, 15 figs, in text.
CHAMBERS, R., JR.
1914. Some physical properties of the cell nucleus. Science, n.s., 40, 824-
827.
1915. Microdissection studies on the physical properties of protoplasm.
Lancet-clinic, Cincinnati, March 27.
1917a. Microdissection studies. I. The visible structure of cell protoplasm
and death changes. Amer. Jour. Physiol., 43, 1-12, 2 figs, in text.
19176. Microdissection studies. II. The cell aster: a reversible gelation
phenomenon: Jour. Exp. Zool., 23, 483-505, pi. 1.
1918. The microvivisection method. Biol. Bull., 34, 121-136, 8 figs, in text.
DOBELL, C. C.
1909. Chromidia and the binuclearity hypothesis. Quart. Jour. Micr. Sci.,
53, 279-326, 25 figs, in text.
DOFLEIN, F.
1911. Lehrbuch der Protozoenkunde (Jena, Fischer), ed. 3, xii, 1043, 931
figs, in text.
ENGELMANN, T. W.
1879. Physiologie der Protoplasma- und Flimmerbewegung. Hermann's
Handbuch der Physiol., 1, 341-408, 5 figs, in text.
1880. Zur Anatomie und Physiologie der Flimmerzellen. Pfliiger's Arch. f.
d. ges. Phys., 23, 505-535, pi. 5.
Tiii/lnr: Newomot or Apparatus in Kui>lul figs, iii text.
FlSCIIKR, A.
1894. t)ber ilif (ii'isscln einiger Flagellaten. Jahrb. f. vviss. Botan., 26, 187-
886, pis. 11, 1L'.
GRIFFIN, L. E.
1910. Kuplnti.1 u-ori'fittt ri sp. nov. I. Structure. Philippine .Tour. SIM., 5,
1'!' 1-31 2, pis. 1-3, 13 figs, in text.
1910ft. Euploti. i ri sp. nov. II. Division. Ibid., 315-36, pis. 4-8.
GfRWITZ, A.
1904. Morphologic und Biologic der Zelle (Jena, Fischer), 437 pp., 239 figs.
in text.
HENNEGUY, L. F.
189'8. Sur le rapports des cils vihratiles avec les centrosomes. Arch. d'Anat.
Micr., 1, 481-96, 10 figs, in text.
JAXICKI. ('.
1915. Untenadumgen an parasitischen Flagellaten. II. Die Gattuiijjrn
Devescovina, Parajoenia, StepTianonymptia, Calonympha. Zeitschr.
wiss. Zool., 112, 573-689, pis. 13-18, 17 figs, in text.
JENNINGS, II. S., AND JAMIESON, C.
1902. Studies on reactions to stimuli in unicellular organisms. X. The
movements and actions of pieces of oiliate Infusoria. Biol. Bull.,
3, 225-34, 4 figs, in text.
JOSEPH, II.
1903. Beitriige zur Flimmerzellen- und Centrosomenfrage. Arb. a. d. Zool.
Inst. Tniv. \Vien, 14, 1-81, pis. 1-3, 3 figs, in text.
KHAINSKT, A.
1910. Zur Morphologic und Physiologic einiger Infusorien (Paramoecium
caudatum) auf Grund einer neuen histologischen Methode. Arch,
f. Prot., 21, 1-60, pis. 1-3, 2 figs, in text.
KITE, G. L.
1912. The nature of the fertilization membrane of the egg of the sea urchin
(Arbacia putirtulata). Science, n.s., 36, 562-64.
1913ininif nx in Kitjilolt . t 4C1
, V/F.K, S.
llMKi. I'nito/.o.mstudion, III. Kiiiilnttx linri>,i. Arb. Zool. lust., riii\. \Vien,
14, Sl-SS, ]1. 1.
1'i'TTF.R. AUG.
1900. Studien iibor Thigimitaxis bei Protiston. Arch. f. Anat. u. IMiysiol.,
I'liysiol. Al.th., 1900, Supplementliuml, ]|>. iM.'i-IHIl', 11 figs, in toxt.
1903. Die Flininierbowrmig. Krgi-bn. d. I'hysiol., 2, 1-1 0., 1." li^s. in text.
ROTHERT. \V.
1894. i !,, , ,| :l s Sdiicksal .lor Cilien bei den Zoiisporcn Phyroinycoten. Ber.
dor deutsch. Botan. Gesellsch., 12, L'I^ 82, pi. 1.
SACITIII. s.
I'.UT. Stuilios on ciliatf.1 colls, .lour. Morph., 29, '2\ 7 i;i;s. pis. 1-4, 1 fig.
in text.
Sciin.uxii. A. 3.
1891. Dio SiisswasMT I'ori.linccn. Flora oder nllfjom. Hot. Zeituns. Neue
Koiho. 49, L'^II-I;!)!!. pis. 8-10.
SCHROEDER, O.
->',. Hi-itriijii* ^ur Kenntnis von Ktrntnr roirulfiix Khrlij;. mid Hlfiitnr rotrichen Infusorien. Zool. Jahrb., Abth. f. Anat.,
15, 1-58, pi. 1, 28 figs, in text.
WHITMORE. E. K.
101 H). Stuilien iiber Kulturamoeben aus Manila. Arch. f. Prot., 23, 81-93,
]>ls. 3, 4.
WU.SON-. C. W.
1916. On the life history of a soil amoeba. T'niv. Calif. Publ. Zool. ,'18.
241-92, pis. 18-23.
YOCOM, H. B.
1918. The neuromotor apparatus of Euplotes patella. Univ. Calif. Publ. Zool.,
18, 337-396, pis. 14-16, 1 fig. in text.
EXPLANATION OF PLATES
PLATE 29
Fig. 1. Transverse incision through three-fourths of the body, after which
the animal maintained normal form. X 800. a.c., anal cirrus; a.c.f., anal cirri
fiber; ant. cyt. f., and nib. f., membranelle fiber; c.v., contractile vacuole; cyt.,
cytostome; f.c., frontal cirri; m.c., marginal cirri; mac., macronucleus; m.f.p.,
membranelle fiber plate; mic., micronucleus; mot., motorium; o.L, oral lip; ph.,
pharynx.
Fig. 2. Transection between ' ' group of three ' ' and ' ' group of four ' ' frontal
cirri. Dorsal view. X 800.
Fig. 3. Transection between "group of four" frontal cirri and the two
ventral cirri. X 800.
Fig. 4. Transection between the two ventral cirri and five anal cirri.
[462]
UNIV. CALIF. PUBL. ZOOL. VOL. 19
[TAYLOR ) PLATE 29
ant. cyt. f.
\ - mot.
m.c.
a. c. f.
PLATE 30
Fig. 5. Incision through the oral lip severing the membranelle fiber. X 800.
ac., anal cirrus; a.c.f., anal cirri fiber; ant.cyt,f. and mb.f., membranelle fiber;
c.v., contractile vacuole; f.e., frontal cirri; m.c., marginal cirri; mac., macro-
nucleus; m.f.p., membranelle fiber plate; mic., micronucleus; mot., motorium;
o.l., oral lip; ph., pharynx.
Fig. 6. Incision through the cytostomal membraneles, cutting the mem-
branelle fiber. X 800.
Fig. 7. Incision cutting the anal cirri fibers between the "group of three"
and "group of four" frontal cirri. X 800.
Fig. 8. Incision between the "group of four" frontal cirri and the two
ventral cirri, severing the anal cirri fibers. X 800.
[464]
UNIV. CALIF. PUBL. ZOOL. VOL. 19
[TAYLOR ] PLATE 30
O.I -^
ant. cyt. f.
-mot.
a.c.f.
---- -V. C.
m.c.
PLATE 31
Fig. 9. Incision anterior ot the anal cirri, cutting the anal cirri fibers.
X 800. a.c., anal cirrus; a.c.f., anal cirri fiber; ant. cyt. f. and mb.f., membranelle
fiber; c.v., contractile vacuole; f.c., frontal cirri; m.c., marginal cirri; mac.,
macronucleus; m.f.p., membranelle fiber plate; mic., micronucleus; mot., motor-
ium; o.l., oral lip; ph., pharynx.
Figs. 10, 11, and 12. Incisions not severing the anal cirri fibers or the mem-
branelle fiber.
[466]
UNIV. CALIF. PUBL. ZOOL. VOL. 19
[TAYLOR] PLATE 31
O.I
ant. cyt. f.
-- mot.
m.c.
-a.c.
c,v.
10
11
12
PLATE 32
Fig. 13. Diagram of the neuromotor apparatus. X 1600. a.c.f., anal cirri
fiber; a.f.p., anal fiber plate; m.f., membranelle fiber; m.f.p., membranelle fiber
plate; mot., motorium.
Pig. 14. Anal cirrus detaching from its fiber plate. The cirris has rotated
90 degrees on its long axis. X 1450. a.c.f., anal cirri fiber; a.f.p., anal fiber
plate; b.p., protoplasmic basal plate; e.g. 2 , large ectoplasmic granules; n.p.,
needle point.
Fig. 15. Anal fiber plate with a portion of its attached fiber distorted by
the needle point. X 1450.
Fig. 16. Diagram of a membranelle showing its relation to the membranelle
plate. X 1450. b.g., basal granule; c.r., ciliary rootlet; f.p., fiber plate.
Fig. 17. Dissected portion of disintegrating membranelle fiber plates at-
tached to the membranelle fiber. X1450. mf.p., membranelle fiber plate;
m.f., membranelle fiber; e.g.,, large ectoplasmic granule; e.g. ls small ectoplasmic
granule.
[468]
UNIV. CALIF. PUBL. ZOOL. VOL. 19
[TAYLOR ] PLATE 32
L ,ac.
15
.e.g.
PLATE 33
Fig. 18. Dorsal view of anal cirrus. X 1450.
Fig. -19. Left lateral view of anal cirrus. X 1450. a.c., anal cirrus; 'b.g.,
basal granule; c.r., ciliary rootlet; p.gl., coagulated protoplasmic globule.
Fig. 20. Ventral view of anal cirri, fibers and plates lying among the dis-
integrating ectoplasm. Anal cirri have turned 90 degrees on their long axis.
X 1450. a.c., anal cirrus; a.c.f., anal cirri fiber showing portion of its plate
dorsal to the cirrus; e.g.^ and e.g.,, small and large ectoplasmic granules.
Fig. 21. Plates and fibers of five frontal cirri. X 1430.
Fig. 21a. Dissociated fiber plates of the ventral cirri with their attached
fibers. X 1450.
Fig. 22. Lateral view of a detached menibranelle previous to disintegration.
X 625.
Fig. 22a. Disintegrating menibranelle showing the component cilia each
with its basal granule and ciliary rootlet. X 625. &.#., basal granule; c.m.,
membranelle cilium; c.r., ciliary rootlet; p.gl., protoplasmic globule.
Fig. 23. A frontal cirrus attached to the disintegrating ectoplasm.. X 625.
e.g., ectoplasmic granule; f.c., frontal cirrus.
[470]
UNIV. CALIF. PUBL. ZOOL. VOL. 19
[TAYLOR ] PLATE 33
-d.f.
21 a
22 a
UNIVEBSITY OF CALIFORNIA PUBLICATIONS (Oontinuea)
11. A Study of the Races of the White-Fronted Goose (Anser albifrons) occur-
ring In California, by H. 8. Swarth and Harold C. Bryant. Pp. 209 222,
2 figures In text, plate 13. October, 1917 _ OB
12. A Synopsis of the Bats of California, by Hilda Wood OrinnelL Pp. 223-404,
plates 14-24, 24 text figures. January 31, 1918 _ _. 2.00
13. The Pacific Coast Jays of the Genus Apheloi-oma, by H. S. Swarth. Pp.
405-422, 1 figure in txt. February 23, 1918 .20
14. Six New Mammals from the Mohave Desert and Inyo Regions of California,
by Joseph Grinnell. Pp. 423-430.
15. Notes on Some Bats from Alaska and British Columbia, by Hilda Wood
Grinnell. Pp. 431-433.
Nos. 14 and 15 In one cover. April, 1918 .15
16. Eevlsion of the Rodent Genus Aplodontia, by Walter P. Taylor. Pp. 435-
504, plates 25-29, 16 text figures. May, 1918 _ .76
17. The Subspecies of the Mountain Chickadee, by Joseph Grinnell. Pp. SOS-
SIS, 3 text figures. May, 1918 16
18. Excavations of Burrows of the Rodent Aplodontia, with Observations on
the Habits of the Animal, by Charles Lewis Camp. Pp. 517-536, 6 figures
in text. June, 1918 20
Index, pp. 537-545.
Vol. 18. 1. Mitosis in tiiimlia microti, by William C. Boeck. Pp. 1-26, plate 1. Octo-
ber, 1917 36
2. An Unnsual Extension of the Distribution of the Shipwora In San Fran-
cisco Bay, California, by Albert L. Barrows. Pp. 27-43. December, 1917. .20
3. Description of Some New Species of Poli/noiilm- from the Coast of Cali-
fornia, by Christine Essenberg. Pp. 45-60, plates 23. October, 1917 .20
4. New Species of Ainplnnomifliie from the Pacific Coast, by Christine Essen-
berg. Pp. 61-74, plates 4-5. October, 1917 __ .16
6. Critliiiliu niriinplttftalmi. sp. nov., from the Hemipteran Bug, EvritophtlKilmus
coni'iru* Stal, by Irene McCulloch. Pp. 75-88, 35 text figures. Decem-
ber, 1917 .15
6. On the Orientation of Erythropsis. by Charles Atwood Kofoid and Olive
Swezy. Pp. 89-102, 12 figures in text. December, 1917 IB
7. The Transmission of Nervous Impulses in Relation to Locomotion in the
Earthworm, by John F. Bovard. Pp. 103-134, 14 figures in text. January,
1918 35
8. The Function of the Giant Fibers in Earthworms, by John F. Bovard. Pp.
135-144, 1 figure in text. January, 1918 _ .10
9. A Rapid Method for the Detection of Protozoan Cysts in Mammalian
Faeces, by William C. Boeck. Pp. 145-149. December, 1917 08
10. The Musculature of Heptanchits maculatus, by Pirie Davidson... Pp. 151-170,
12 figures in text. March, 1918 _ 35
11. The Factors controlling the Distribution of the Polynoldae of the Pacific
Coast of North America, by Christine Essenberg. Pp. 171-238, plates 6-8,
2 figures in text. March, 1918.... .76
12. Differentials in Behavior of the Two Generations of Salpa democratica
Relative to the Temperature of the Sea, by Ellis L. Michael. Pp. 239-298,
plates 9-11, 1 figure in text. March, 1918 .88
13. A Quantitative Analysis of the Molluscan Fauna of San Francisco Bay, by
E. L. Packard. Pp. 299-336, plates 12-13, 6 figs, in text. April, 1918 .40
14. The Neuromotor Apparatus of Euplotes patella, by Harry B. Yocom. Pp.
337-396, plates 14-16. September, 1918 .70
15. The Significance of Skeletal Variations in the Genus Peridinium, by A. L.
Barrows. Pp. 397-478, plates 17-20, 19 figures In text. June, 1918 90
16. The Subclavian Vein and its Relations in Elasmobranch Fishes, by J.
Frank Daniel. Pp. 479-484, 2 figures in text. August, 1918 .10
17. The Cercaria of the Japanese Blood Fluke, Srhisinsoma japonicum Kat-
surada, by William W. Cort Pp. 485-507, 3 figures in test.
18. Notes on the Eggs and Miracidia of the Human Schlstosomes, by William
W. Cort. Pp. 509-519, 7 figures In text.
Nos. 17 and 18 in one cover. January, 1919 _ .35
Index in preparation.
UNIVERSITY OP CALIFORNIA PUBLICATIONS (Continued)
Vol. 19. 1. Reaction of Various Plankton Animals with Reference to their Diurnal
Migrations, by Calvin O. Esterly. Pp. 1-83. April, 1919_ _ .86
2. The Pteropod Desmoptcrus pacificus (sp. nov.), by Christine Essenberg.
Pp. 85-88, 2 figures in text. May. 1919 05
3. Studies on Giardia microti, by William C. Boeck. Pp. 85-136, plate 1, 19
figures in text 60
4. A Comparison of the Life Cycle of Crithidia with that of Trypanosoma in
the Invertebrate Host, by Irene McCulloch. Pp. 135-190, plates 2-6, 3
figures in text. October, 1919 60
5. A Muscid Larva of the San Francisco Bay Region which sucks the Blood
of Nestling Birds, by O. E. Plath. Pp. 191-200. February, 1919 J.O
6. Binary Fission in Collodictyon triciliatum Carter, by Robert Clinton Rhodes.
Pp. 201-274, plates 7-14, 4 figures In text. December, 1919 1.00
7. Tie Excretory System of a Stylet Cercarla, by William W. Cort. Pp. 275-
281, X figure in text. August, 1919 10
8. A New Distome from Sana aurora, by William W. Cort. Pp. 283-298,
5 figures in text. November, 1919 20
9. The Occurrence of a Rock-Boring Isopod along the Shore of San Fran-
cisco Bay, California, by Albert L. Barrows. Pp. 299-316, plates 15-17.
December, 1919 25
10. A New Morphological Interpretation of the Structure of Noctihica, and
its Bearing on the Status of the Cystoflagellata (Haeckel), by Charles
A. Kofoid. Pp. 317-334, plate 18, 2 figures in text. February, 1920 25
11. The Life Cycle of Echinostoma revolutum (Froelich), by John C. Johnson.
Pp. 338-388, plates 19-25, 1 text figure. May, 1920 60
12. On Some new Myriopods Collected in India in 1916 by C. A. Kofoid, by
Ralph V. Chamberlin. Pp. 389-402, plates 26-28. August, 1920 20
13. Demonstration of the Function of the Neurotnotor Apparatus in Euplotes
by the Method of Microdissection, by Charles V. Taylor. Pp. 403-470,
plates 29-33, 2 figures in text. October, 1920 85
Vol.20. 1. Studies on the Parasites of the Termites. I. On Streblomastix strix, a
Polyinastigote Flagellate with a Linear Plasmodial Phase, by Charles
Atwood Kofoid and Olive Swezy. Pp. 1-20, plates 1-2, 1 figure in text.
July, 1919 .-. 25
2. Studies on the Parasites of the Termites. II. On Trichamitus termitidis,
a Polymastigote Flagellate with a Highly Developed Neuromotor System,
by Charles Atwood Kofoid and Olive Swezy. Pp. 21-40, plates 3-4, 2
figures in text. July, 1919 25
3. Studies on the Parasites of the Termites. III. On TricJumympha campanula
Sp. Nov., by Charles Atwood Kofoid and Olive Swezy. Pp. 41-98, plates
5-12, 4 figures in text. July, 1919 .75
4. Studies on the Parasites of the Termites. IV. On Leidi/opsis iphaerica
gen. nov., sp. nov., by Charles Atwood Kofoid and Olive Swezy. Pp.
99-116, plates 13-14, 1 figure in text. July, 1919 25
5. On the Morphology and Mitosis of Chilomastix mesnili (Wenyon), a Common
Flagellate of the Human Intestine, by Charles A. Kofoid and Olive Swezy.
Pp. 117-144, plates 15-17, 2 figures in text. April, 1920 35
6. A Critical Review of the Nomenclature of Human Intestinal Flagellates,
Ce.rcomonas, Chilomastix, Trichomonas, and Giardia, by Charles A. Kofoid.
Pp. 145-168, 9 figures in text. June, 1920 35
Vol. 21. 1. A Revision of the Microtus calif ornicus Group of Meadow Mice, by Rem-
ington Kellogg. Pp. 1-42, 1 figure In te-rt. December, 1918 _ .50
2. Five New Five-toed Kangaroo Rats from California, by Joseph Grinnell.
Pp. 43-47. March, 1919 05
3. Notes on the Natural History of the Bushy-Tailed Wood Rats of California,
by Joseph Dixon. Pp. 49-74, plates 1-3, 3 figures in text. December, 1919 .25
4. Revision of the Avian Genus Passerella, with Special Reference to the Dis-
tribution and Migration of the Races in California, by H. 8. Swarth.
Pp. 75-224, plates 4-7, 30 figures in text. September, 1920 1.75
5. A Study of the California Jumping Mice of the Genus Zapus, by A. Brazier
Howell. Pp. 225-238, 1 text figure. May, 1920 15
Vol. 22. 1. A Quantitative and Statistical Study of the Plankton of the San Joaquin
River and its Tributaries in and Near Stockton, California, in 1913,
by Winfred Emory Allen. Pp. 1-292, plates 1-12, 1 text figure. June,
1920 S.OO
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