The Journal of experimental zoology . our-segment thoracic pieces, left by thethoracic cuts in lots two and three, the development does not followthis course. The opercular bud is from the start very evidentlydifferent from the others, being larger and more spherical than thebranchial buds proper. This is well shown in the figures.(Figs. 25 and 26.) The branchiae in this case, however, are alsothicker and shorter than the corresponding ones where the bodyremains intact. It is very evident that while in the one casewhere the body is intact the operculum passes through a distinct 8o Charles Zele
The Journal of experimental zoology . our-segment thoracic pieces, left by thethoracic cuts in lots two and three, the development does not followthis course. The opercular bud is from the start very evidentlydifferent from the others, being larger and more spherical than thebranchial buds proper. This is well shown in the figures.(Figs. 25 and 26.) The branchiae in this case, however, are alsothicker and shorter than the corresponding ones where the bodyremains intact. It is very evident that while in the one casewhere the body is intact the operculum passes through a distinct 8o Charles Zeleny. branchial stage before showing even a beginning of an opercularknob, in the other case where only the anterior two or four seg-ments remain the operculum appears as such from the start. Unfortunately the animals in the last two lots did not live longenough to show whether or no the final outcome would have beenthe same in the two cases. In fact none of them showed anypinnules on the branchiae at the time of death. Notwithstanding. Fig. ampullifera. Regenerating branchial circlets. Nine days after operation (X 40).Operation: Autotomy of both branchial circlets at breaking joint and removal of body posterior tosecond thoracic segment. Note pronounced opercular differentiation on both sides. these limitations it is evident that we have a definite accelerationof the rate of differentiation of the opercula. Two probable factors may be mentioned as concerned in thebringing on of the acceleration, i. The shock of the transversedivision of the body may lead to such an increase in rapidity ofdifferentiation. 2. The small size of the piece itself may directlyinfluence the process and bring about such a differentiation. Thisaction may result because of the difference in the interactions of theorgans in the one case as compared with the other. Compensatory Regulation. 81 V. REGULATION OF THE RATE OF GROWTH AND NATURE OF DIF-FERENTIATION DURING REGENERATION OF THE CHELAE OFG
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Keywords: ., bookauthorwi, bookcentury1900, bookdecade1900, booksubjectzoology
