296 MORGAN. [VOL. I. 



Palaemon and Sicyonia were removed sometimes an eye and 

 sometimes an antenna reappeared. Chantran, in 1873, also 

 noticed that if half of the eye-stalk of the crayfish were cut off 

 a new eye appeared. If the entire eye were excised, it was 

 not regenerated. It is interesting to note that in the hermit 

 crab the new eye came in when the stalk was cut off near its 

 outer end, and an antenna-like structure appeared in five out 

 of ten cases in which the stalk was cut off near its base. 



Antennae. --^\\\e individuals had begun to regenerate a new 

 antenna from the old basal joint. Five of these had long 

 segmented antennae, one-half or one-fourth as long as the fully 

 formed antenna (Fig. 17). Four of the nine had smaller buds, 

 showing generally evidences of segmentation (Fig. 16). Only 

 one of the ten survivors had not regenerated at all. 



Antennulcs. - -One had completely regenerated; two, on the 

 same individual, were two-thirds the full length; three had new 

 short buds, and one of these individuals had also lost the other 

 antennule, but had not regenerated it. A sixth individual had 

 not regenerated. Four individuals died during the time of the 

 experiment. 



Maxillipeds. - - The third and sometimes the second maxilli- 

 ped were cut off from one side. In all eight survivors (of ten 

 operated upon) the parts removed had begun to regenerate. In 

 two cases the third maxilliped was nearly as long as the normal 

 appendage. In five cases it was represented by two small out- 

 growths from the basal joint (Fig. 18). In one individual a very 

 short bud was present. The second maxilliped had been cut 

 off in five of the above cases. In four individuals it was repre- 

 sented by two new processes growing out of the basal joint. 

 In one case the new maxilliped was half the normal size. A 

 part of the first maxilliped had been cut off in one instance and 

 was regenerating. 



Abdominal Appendages. - - Of twenty-four individuals from 

 which the abdominal appendages had been cut off, fourteen 

 were alive on September 15. Only two had regenerated the 

 first abdominal appendage (Figs. 21, 23); while ten other indi- 

 viduals from which the same appendage had been cut off had 

 not regenerated. Two had not had this appendage cut off. 



