Regeneration in Coniponiul Eyes of Crustacea 223 



complete record nine developed heteromorphic appendages and all 

 of them within thirty-three days. Two of the remaining five, 

 which moulted at the end of twenty-one days and then died, might 

 perhaps have developed an appendage had they lived through a 

 second moult. Each of them showed a very small bud where the 

 eye had been removed. 



B CRANGON 



/ Regeneration of Heteromorphic A ppendages 



In some respects Crangon appears to be a favorable form for 

 experimental work. They are less disastrously affected by the 

 operation than the others worked upon. The entire eye was 

 removed from twenty-two Crangon and not one of the number 

 died from the effects of the operation. 



This entire number was of the same series. The experiment 

 covered a period of thirty-three days, August 3 to September 4, 

 inclusive. During that time with one exception each individual 

 moulted at least once and fourteen moulted a second time. Three 

 of those that moulted but once were eaten by their comrades soon 

 after the moult. The evident hardiness of the Crangon and the 

 frequency of the moults would seem to be favorable conditions for 

 regeneration. 



Results, however, show only one individual that regenerated a 

 heteromorphic appendage, the others showing no regeneration. 

 Fig. 38a and b shows surface views of this one regenerated ap- 

 pendage. The animal which developed it moulted on the fourth 

 day after the operation. At that time there was no evidence of 

 regeneration. Seventeen days later another moult occurred and 

 an appendage of six segments, with sensory hairs near the tip, 

 appeared. The appendage measures four-fifths of the length of 

 the eye on the opposite side and projects forward at the same 

 angle. The outline of the optic nerve can be seen extending 

 through the proximal half of the appendage. 



2 Cases that Shoiu No Especial Regeneration 



Twenty-one out of twenty-two Crangon showed no regeneration. 

 Four of these died within nine days after the operation and so 



