PINNOTHERES. 53 



Some of the species live inside bivalve shells, but the 

 greater number live free. Some of the exotic species, such 

 as the Land Crabs of the West Indies, only visit the sea 

 to hatch their eggs ; others, as the species of Ocypode, can 

 run with great agility. 



Fam. PINNOTHERIB^ Leach. 



Carapace circular, at least as long as wide. Abdomen of 

 the male with the second joint much narrower than the 

 corresponding part of the sternal shield. Front generally 

 very narrow. Eye-stalks very short. Fourth joint of outer 

 jaw-feet fixed at the top or outer angle of the third joint. 



The species of this family are of small size, and they live 

 parasitically within the lobes of the mantle of bivalve shells. 

 The females are much larger and much more soft than their 

 mates. 



Gen. 16. PINNOTHERES, Latr. 



Front wide enough to conceal beneath it the inner an- 

 tennas. The outer jaw-feet, when closed, semilunar in front, 

 very wide behind; the inner antennse transverse. Carapace 

 and body circular, and rounded above. Abdomen of male 

 very small; of female much swollen and wider than the 

 sternal shield. 



