Compensatory Regulation. 



85 



specimens. In the cases where both eyestalks were removed 

 the moults came sooner (14 and 23 days) than when only one was 

 removed (56, 58 and 61 days). Here again, therefore, there is a 

 hastening of the physiological process in the cases of a greater 

 disturbance as compared with those of a lesser disturbance of the 

 organism. 



3. Alpheus Dentipes. 



I, Introduction and Review of Former Work. 



The reversal of the cutting and snapping chelae of Alpheus has 

 been demonstrated and the process studied by Przibram ('01, '02) 

 and recently by Wilson ('03) and 

 Brues ('03, '04). It has been 

 shown that when the snapping 

 claw is removed, the cutting chela 

 of the opposite side is differen- 

 tiated into a snapping chela, while 

 in place of the removed snapping 

 chela a new cutting chela is 

 developed. When the cutting 

 chela alone is removed there is 

 no reversal, a new cutting chela 

 developing in place of the old. 

 When both chelae are removed 

 there is again no reversal, a new 

 snapping chela being regenerated 

 in place of the old snapping and ^■°- ^'^• 



a new cutting chela in place of the '^^'^'^ °^ Alpheus dentipes (X 4). Left-hand 



W^- T ^1 1 ^^ figure: cutting chela. Right-hand figure: snap- 



cuttmp-one. In the latter case , , t^ ■ ,■ \ , , 



_.^ . " . A 1 • P'"S chela. Dotted lines represent the lengths 



Frzibram,workmgon A. dentipes measured (see text, p. 91). 

 and A. platyrrhynchus mentions 



the fact that the newly regenerated cutting chela is relatively 

 larger as compared with the snapping chela than in the animal 

 before the operation. Wilson's result on the Beaufort, N. C, 

 species (H. heterochelis) agrees with that of Przibram except that 

 in the case where both chelae were removed the new cutting chela 

 does not approach the new snapping chela as nearly as in the 

 species upon which Przibram worked. Wilson further added the 

 interesting result that when the snapping chela is removed and the 

 nerve leading to the cutting chela is cut below the breaking joint 



