Compensatory Regulation. 83 



showed an abnormality in that the smaller regenerated chela had 

 two pinchers at its end. This case will be described in a separate 

 note at another time.^ 



d. Two normal male specimens kept in glass dishes for 62 

 days did not moult or show any changes. They were fed on 

 fragments of Mytilus in the same manner as the others. 



2. Experiments on Females. 



a. Removal of Otje Chela (right or left). Two of the six 

 specimens moulted before the completion of the' experiment. In 

 one of these the regenerated chela was a trifle smaller than the 

 opposite one. In the other the two chelae, the old and the regener- 

 ated one, were nearly equal in size after the moult. One of these 

 specimens moulted 56 days, the other 62 days after the operation. 



b. Removal of Both Chelce. Only three specimens were oper- 

 ated on in this way. All had moulted within 46 days after the 

 operation. The new animals regenerated two new and equal 

 chelae. The regenerated structures, therefore, repeat the char- 

 acter of the removed appendages. 



3. The Rate of Regeneration and of Moulting After the Opera- 

 tion. (Male and Female.) 



The data show very plainly that the moulting takes place 

 sooner in the cases where both of the chelae are removed than in the 

 cases where only one or none are removed. In fact all three mem- 

 bers of the female set with both chelae removed moulted before any 

 of those with only one chela removed had done so. It does not 

 seem possible that the matter of accident can come in here as there 

 are too many cases both as regards this point and as regards other 

 related ones. 



A general comparison in both males and females of the cases 

 in which both chelae were removed with those in which only one 

 or none were removed bring out an interesting result. 



1. Time of moulting. The specimens zuith both chelce removed 

 moulted sooner than those with only one chela removed. 



2. The regenerating buds in the specimens where both chelce had 

 been removed were in general larger than the corresponding buds 



Biol. Bull., 



05. 



