200 CRUSTACEANS. 



ceding species. It feeds on fish, or on mussel, which must be brought 

 almost in contact with the mouth, or otherwise it may pass undiscovered. 

 When fed, the specimen first securing a morsel is assailed by its com- 

 panions in their endeavours to carry it off. Ah 1 are otherwise extremely 

 pacific. 



I know not how to interpret certain passages regarding " the 

 Spider Crab in a state of ecclesis or moulting," as related in the Annals 

 and Magazine of Natural History, Vol. VIII. 



There the observer says, " A few days since a Spider Crab was sent 

 to me alive, taken in the act of changing its coat. The operation was 

 singular. The upper and lower shell being parted, the legs were with- 

 drawn from their old cases, and served as a lever to detach the under 

 shell from the upper. Some exertion of the legs was necessary to raise 

 the upper shell. This had been accomplished, but it was not entirely 

 detached from the body when brought to me. The body was quite soft, 

 and the hard skin of about the consistence of parchment. In fact the 

 change was almost completed." 



The exuviation of the specimen, Plate L. fig. 2. took place on the 

 18th of September, when the animal, as there represented, appeared 

 considerably larger than previously. It seemed to have escaped from 

 the hind part of the shell, which was quite entire elsewhere. This old 

 shell was very thin, the hairyness of the claws and bristles on the rest 

 alike conspicuous. 



With sufficient attention to preserve the purity of the water, these 

 animals will survive months in confinement. 



PLATE L. 



Fio. 1. Cancer phalangium, the Spider Crab. 



2. Another specimen. 



3. Apron of the female covering immature spawn. 



4. Spawn. 



5. Spawn in March, enlarged. 



6. Portion of spawn, more enlarged. 



