18 HARVARD UNIVERSITY. LIBRARY OF THE MUSEUM OF COMPARATIVE ZOOLOGY. GIFT OF ALEXANDER AGASSIZ. MI 3 8 19r.«J The Reversal of the Direction of Differentiation in the Chelipeds of the Hermit Crab von John Diederich Haseiuan With 1 plate and 1 figure in text Sonderabdruck aus dem Archiv für Entwicklungsmechanik der Organismen Herausgegeben von Prof. Wilh. Roux in Halle a/S. XXIV. Band. 4. Heft Ausgegeben am 17. Dezember 19(t7 Leipzig Wilhelm Engelmann S* 1907 Das Archiv für Entwicklungsmechanik der Organismen steht offen jeder Art von exakten Forschungen über die „Ursachen" der Entstehung, Erhaltung und Rückbildung der organischen Gestaltungen*) Bis auf weiteres werden auch kritische Referate und zusammen- fassende Ubersichten Uber andern Orts erschienene Arbeiten gleichen Zieles, sowie Titelübersichten der bezüglichen Literatur aufgenommen. Das Archiv erscheint zur Ermöglichung rascher Veröffent- lichung in zwanglosen Heften sowohl in bezug auf den Umfang, wie auch auf die Zeit des Erscheinens; mit etwa 40 Druckbogen wird ein Band abgeschlossen. Die Herren Mitarbeiter erhalten unentgeltlich 40 Sonderdrucke ihrer Arbeiten; eine größere Anzahl Sonderdrucke wird bei Voraus- bestellung gegen Erstattung der Herstellungskosten geliefert, unter der Voraussetzung, daß die Exemplare nicht für den Handel be- stimmt sind. Referate, Besprechungen und Autoreferate werden mit Ji 40.— für den Druckbogen nach Abschluß des Bandes honoriert. Die Zeichnungen der Textfiguren sind im Interesse der rascheren Herstellung womöglich in der zur Wiedergabe durch Zinkätzung geeigneten Weise auszuführen**). Die Textfiguren sind vom Texte gesondert beizulegen; an den Einfligungsstellen im Texte sind die Nummern der bezüglichen Figuren anzubringen. Sind die eigentlich für den Text bestimmten, in linearer bzw. punk- tierter Manier hergestellten Figuren sehr zahlreich, so werden sie besser auf Tafeln beigegeben. Tafeln sind in der Höhe dem Format des Archivs anzupassen; für jede Tafel ist eine Skizze Uber die Verteilung der einzelnen Figuren beizufügen. Die Einsendung von Manuskripten wird an den Herausgeber erbeten. Der Herausgeber: Der Verleger: Prof. Dr. Wilh. Roux, Wilhelm Engelmann, Halle a/d. S. (Deutschland). Leipzig. *; Den in niohtdeutscher: in englischer, italienischer oder franzö- sischer Sprache zu druckenden Originalabhandlungen ist eine kurze Zu- sammenfassung der Ergebnisse, sei es in der Sprache des Originals oder in deutscher Sprache beizufügen. **! Dies geschieht in linearerbzw.punktierterZeichnung mit tief schwarzer Tinte oder Tusche, kann aber leicht auch durch nachträgliches Überzeichnen der Bleistiftzeichnung mit der Tuschfeder hergcsteUt werden. Wer jedoch im Zeichnen mit der Feder nicht geübt ist, kann die einfache Bleistiftzeichnung ein- senden, wonach sie von technischer Seite überzeichnet wird. Die Bezeichnungen (Buchstaben oder Ziffern) sind bloß schwach mit Bleistift einzutragen, sofern sie der Autor nicht kalligraphisch herzusteUen vermag. Anweisungen für die Herstellung wissenschaftlicher Zeichnungen zu Textfiguren mit Aus- führungen über die einzelnen Herstellungsarten und Proben derselben stellt die Verlagsbuchhandlung den Herren Mitarbeitern gern unentgeltlich zur Verfügung. The Reversal of the Direction of Differentiation in the Chelipeds of the Hermit Crab1). By John Diederich Baseman. With plate XXIX and 1 figure in text. Eingegangen am 22. Oktober 1907. This work was done in the laboratory of the Bureau of Fisher- ies at Woods Hole, Mass.2) and in the zoological laboratory of Indiana University. The problem presented itself to the writer during 1906 and 1907 , while working on the direction of differen- tiation in regenerating crustacean appendages. At that time three cases of reversal of the direction of differentiation were observed, and they were due apparently to the character of the operation. Consequently this work was taken up to see if it were possible to reverse the direction of differentiation by means of a series of operations. I. Method and Material. For the investigation of the direction of differentiation, several species of crustacea were used but none proved to be so good as Eupagurus longicarpus, the common hermit crab at Woods Hole. A spider-, fiddler-, and mud-crab were used but no cases of a reversal of the direction of differentiation were obtained from them. Also two species of Amphipods were tried but they proved to be of no value for this work. ') Contributions from the zoological laboratory of Indiana University. No. 91. 2) I acknowledge my indebtedness to the Bureau of Fisheries and its di- rector, Dr. Sumner, for the opportunity to carry out this work. I am also much i ndebted Dr. Zeleny for reading the proof. 664 John Diederich Ha-eman My method was based on the fact that regenerating chelipeds differentiate from the tip toward the base, while regenerating clawed legs differentiate from the base toward the tip. If by a series of operations one can change a cheliped into a clawed leg or vice versa, then the chances of reversal of the direc- tion of differentiation are extremely great. I tried cutting the clawed legs and chelipeds at various levels and angles, as well as making slits in the remaining stumps, and I finally adopted the following plan, because it, as a rule, produced a greater number of monstrosities and a fewer number of deaths than any other: The chelipeds were removed at their breaking joints and allo- wed to regenerate to the stage in which the new pinchers are start- ing to differentiate from the mass of regen- erating tissue; then the tips of the regen- erating chelipeds were cut off and longi- tudinal slits were made in the sides of the remaining stumps by pushing the pointed end of a lance into them. This is shown by the text-figure. In some cases more than the part which was to have formed the pincher was removed; and in still others the tip was cut off before the pinchers had started to differentiate. The individuals were kept separately in finger bowls. They were fed twice a week on pieces of mussels, and the water was changed every two days. > a b c n The plane of removal of tho tip. b The puncture of the side. c The level of the first operation. II. Difficulties. There were many difficulties encountered in dealing with Eupa- gurus longicarpus. In the first place it was a difficult matter to get them out of their shells without breaking the shells. However, when they were taken out of the water and turned upside down the crabs usually crawled out a greater distance than usual, and could easily be pulled out far enough for the operation, if they were drawn out slowly. The operations always killed a great per cent of the animals. In my first series of sixty individuals, twenty died after the first operation, and ten more died after the second operation. Even more The Reversal of the Direction of Differentiation in the Chelipeds etc. 665 perplexing than this is the fact that individuals containing abnormal appendages never lived longer than two moults after the second operation. Furthermore, it was by no means an easy task to cut and slit the delicate regenerating appendages at desired levels. The advantage of using Eupagurus longicarpus is the abundance of material, the ease with which it can be kept alive, and the rapi- dity of the moult. Individuals of average size moulted every two or three weeks, while the mud-, spider- and fiddler-crabs did not moult oftener than once a month. I was unable to keep a sufficient number of the sand fleas alive long enough to do any work on the reversal of the direction of differentiation with them. 111. Data. A. The Normal Direction of Differentiation. When the chelipeds of Eupagurus longicarpus are removed at any level, they differentiate from the tip toward the base. The clawed legs differentiate from the base toward the tip. This same plan of direction of differentiation is true for the common mud-, and spider-crab, and I think that it is also true for the fiddler-crab as well as for the two species of sand-fleas, but so far I have not been able to get a sufficient number of stages to be absolutely certain. This plan of direction of differentiation for the crab is the same as has been recorded for several other crustacea. B. The Reversal of the Direction of Differentiation. I was unable to produce any change in the direction of dif- ferentiation in the clawed legs of Eupagurus. In the case of the chelipeds several abnormal young stages were produced, but many of the crabs died before they developed sufficiently well to show anything conclusive. However, a few lived long enough to moult once or twice after the second operation, and some of these are described in the following notes: No. 1. The left cheliped was cut off at the end of the first segment, July 19th. The crab moulted July 21st. The side of the leg was punctured July 27th. It moulted again August 4th and died August 5th. This cheliped is about normal excepting that the seg- ment next to the pincher is wanting, and the pointed parts of the pincher are segmented into two pieces. After the pincher was formed, the dactylopodite and propodite began to segment from the base 666 John Diedericli Haseman toward the tip, and the tip kept elongating until the time of death of the crab. No. 2. The right cheliped of another crab was removed at the same level as No. 1. The crab moulted July 29th. The tip of the regenerating cheliped was cut off and the side of the remaining stump was punctured August 5th, at which time there was only a mere trace of regeneration. The crab moulted again August 22d, and was killed September 1st. Three new segments differentiated from the base toward the tip. From August 5th to September 1st was plenty of time for a normal pincher to regenerate. No. 3. This is a left cheliped which was cut off at the end of the first segment July 19th and the basal segment was then slit. The crab moulted July 23d, and August 5th the pincher which had regenerated was cut off again and the side of the remaining stump of the cheliped was punctured. The crab moulted again on August 9th, and died August 22d. The tip or fifth segment was just differentia- ting and there was no sign of the pincher. The direction of diffe- rentiation was from the base toward the tip. No. 4. This is a left cheliped which was cut off at its base July 21st. The crab moulted July 25th. There was only a little regeneration August 5th when the base was reslit. The crab moulted again August 12th. The tip segment was very small August 16th. The crab died August 19th, at which time the tip segment was al- ready of considerable size. There were no signs of a pincher on August 19th, and it was evident from the observations on the living specimen, that the direction of differentiation had been reversed. No. 5. This right cheliped was cut off at its breaking joint on August 4th. The regenerated pincher was cut off and the side of the remaining stump was punctured August 18th. The crab was killed September 1st, at which time the tip segment was just forming. Apparently the 4th and then the 3d segment was completed after the pincher was removed. The 5th and then the 6th was formed some time afterwards. The 6th segment is just forming and there is no pincher. Normally the pincher is formed first. No. 6. This right cheliped was removed at its breaking joint on August 4th. The regenerated pincher was cut off and the re- maining stump was punctured August 18th. The crab was killed September 1st, at which time there were seven segments instead of six. The first four segments were normal, while the tip or 7th seg- ment was quite long and showed signs of division near the tip. The Reversal of the Direction of Differentiation in the Chelipede etc. 667 Apparently the 4th and then the 3d segment was completed after the pincher was cut off. A new proliferation took place and the 5th, 6th, and then the 7th segments were formed from it. No. 7. The right cheliped was removed August 4th at the breaking joint, and it then received the same treatment as No. 6. The 6th segment is just forming but there is no sign of a pincher. However, in this case the new basal segments were perhaps formed in the normal way, and the fourth new segment has arisen from the second proliferation and has not had enough time to differentiate. Only these seven cases out of the fifteen which were obtained, will be recorded because they are the characteristic ones. IV. Discussion. It appears that the reversal in the direction of differentiation is due to a disturbance in the physical conditions existing in the re- generating appendages, because a simple cut or slit at any level is not sufficient to produce the reversal. However, if when a re- generating cheliped has attained the proper size, the tip is cut off and the remaining stump punctured near the middle, then the direction of differentiation is reversed, apparently because the balance of the physical conditions is altered. In other words the tension which accompanies the formation of a pincher is destroyed by the operation, and a new tension is formed by the two cuts pulling in opposition. Consequently the tension originating from the two wounds seems to neutralize the one which was to accompany the formation of the new pincher. As a result the new segments are formed from the base toward the tip instead of from the tip toward the base. Of course if all the remaining basal segments are almost completely differen- tiated at the time when the pincher is cut off, they differentiate in the normal way; but the new segments which are formed from the second proliferation differentiate from the base toward the tip, as in figure six. If more than the pincher is cut off the same results are obtained. If the tip of the regenerating knob is cut off before the pincher has started to differentiate, then there is a complete reversal, and all of the segments are differentiated in their order from the base toward the tip, as is shown by figure two. The following notes not related to the main theme were made during the course of the experiments: Archly f. Entwicklungsmeckanik. XXIV 44 668 John Diederich Haseiuan 1) The regenerating chelipeds are enclosed in sacks. No differ- entiation is visible before three days after the operation. 2) No double legs were obtained when the bases of amputated legs were slit and allowed to regenerate. 3) It is a peculiar fact that as a rule there are only six seg- ments in the new leg. Only one has seven segments. Many have less than six, but they show signs of further differen- tiation. V. Summary. 1) When the chelipeds of Eupagurus longicarpus are removed at their breaking joints, they differentiate from the tip toward the base. The clawed legs differentiate from the base toward the tip. 2) If the tip of a regenerating cheliped is cut off at about the time when the pincher is differentiating, and the remaining stump is punctured near its middle, the direction of differentiation is quite often reversed. The reversal is apparently due to the disturbance of the physical conditions existing in the regenerating cheliped. Zusammenfassung, 1) Wenn die ScherenftiGe von Eupagurus longicarpus an ihren Brech- gelenken abgetrennt werden, so differenzieren sie sich von der Spitze nach der Basis zu. Die KlauenfiiGe differenzieren sich von der Basis nach der Spitze zu. 2) Wird die Spitze eines in Regeneration begriffenen ScherenfaGes abge- schnitten ungeiahr zur Zeit, wenn sich die Zange differenziert, und wird der zuriickbleibende Stumpf nahe seiner Mitte angestochen, so wird ganz hiiufig die Differenzierungsrichtung umgekehrt. Die Umkehrung beruht anscheinend auf einer Sttfrung der physischen Bedingungen, die in dem ScherenfuGe wahrend der Regeneration bestehen. Explanation of Plate. Plate XXIX. The arrows mark the level of the first operation. The figures were made with a camera. No. 1. Left cheliped cut at the end of first segment July 19th. Moulted July 21st. The regenerating leg was punctured July 27th. The crab died August 6th. (x 16) No. 2. Right cheliped cut off at end of the first segment July 19th. Moulted July 29th. The tip was slit and the side was punctured August 5th. Moulted again August 22d, and was killed September 1st. (x 1G) No. 3. Left cheliped cut off at the end of the first segment July 19th. Moulted July 23d. The pincher was cut off and the remaining stump was punctured The Reversal of the Direction of Differentiation in the Chelipeds etc. 669 August 5th. The animal moulted again August 9th and died August 22d. (x 16) No. 4. Left cheliped cut off at its base July 21st. The animal moulted July 25th. The base was split August 5th. The crab moulted again August 12th. Died August 19th. (x 16) No. 5. Right cheliped cut off at the breaking joint August 24th. The pincher was cut off and the remaining stump punctured August 18th. The crab was killed September 1st. (x 16) No. 6. Right cheliped cut off at the breaking joint August 4th. The pincher was cut off and the side of the remaining stump punctured August 18th. It was killed September 1st. No. 7. Right cheliped cut off at the breaking joint August 4th. The pincher was cut off and the side of the remaining stump was punctured August 18th. The crab was killed September 1st. (x 16) 44« Areltiv fur Entwicklungsniechanil: Bd. XXIV. Taf. XXIX. Haseman. Verlag von Wilhelm Engelmann in Leipzig. G :; TERLAG VON WILHELM EXGELMANN IN LEIPZIG;: Soeben ist erschienen: Mechanismus und Vitalismus in der Biologie des neunzehnten Jahrhunderts Ein geschichtlicher Versuch von Karl Braeunig 7 Bogen, gr. 8. Geheftet Jl 2.40 | Die Physiologie des Lesens und Sehreibens von Emile Jayal Autorisierte Übersetzung nach der 2. Auflage des Originals nebst Anhang über Deutsche Schrift und Stenographie von Dr. med. F. Haass Augenarzt in Viersen Mit 101 Figuren im Text und einer Tafel 351 S. 8. M 9.—. Chemie der höheren Pilze Eine Monographie von Dr. Julius Zellner VI und 257 S. gr. 8. Je 9.—. '• ■'■>-' Inhalt des vierten Heftes. s«ite A. Kirchner, Die Architektur der Metatarealien des Menschen. (Mit 18 Fig. im Text.) 639 John Diederich Haseman, The Direction of Differentiation in Regenerating Crustacean Appendages. (With plates XIX—XXVII.)........ 617 Leo Loeb, Beitrage zur Analyse des Geivebewachstnms. I. Uber Transplan- tation regenerierenden Epithels und uber Serientransplantation, von '* ^fehd • "J":. .-"> £„ . 638 Georg Duncker, liber Kegeneration des Schwanzendcs bei Syngnathiden. (Zweite Mitteilung.) (Mit Tafel XXVIII und 2 Fig. im Text.) . . . C56 John Diederich Haseman. The Reversal of the Direction of Differentiation in the Chelipeds of theTIermit Crab. (With plate XXIX and 1 figure in text.) ' •. 663 Autoreferate aus dem Journal of Experimental Zoology Vol. IV, No. 2 . 670 Autoreferat: Max Mundex, Der Chtonoblast in seinen Beziehungen zur Entwicklungsmechanik 677 Wilhelm Rol'x, Bemerktmg zu Max Mundens Autoreferat uber seinen Chtonoblast und uber die angeblich gelungene Hervorbringung kiinstlicher Lebewesen 684 W. Roux, Besprcchungen 686 Neueste Literatur 696 :: VERLAG VON WILHELM ENGELMANN IN LEIPZIG;; Soeben erschieneu: Archhelenis und Archinotis Gesammelte Beitrage zur Geschichte der neotropischen Region von Hermann von Jhering Mit einer Figur im Text und einer Xarte 22 Bogen. 8. Geheftet Jl 6.—. Die Entwicklung der Kontinente und ihrer Lebewelt Ein Beitrag zur vergleichenden Erdgeschichte von Dr. Theodor Arldt Mit 17 Figuren und 23 Karten. 47 Bogen gr. 8. Geheftet J( 20.—, in Leinvrand gebunden M 21.60. ICin auafnlirliclier* Prospckt st olit zu Dienstcn. Druck von Breitkopf & Hartel in Leipzig