CRUSTACEA OF THE DEEP SEA 131 



be altogether prohibitive, for there are a good many 

 characteristically deep-sea Crustacea, such as the 

 Eryonidea, that have small eggs and presumably a 

 larval metamorphosis. 



The uniformity of the physical conditions over 

 vast areas in the deep sea is no doubt the cause of 

 the enormously wide geographical range of many 



Fig. 45 — A Deep-sea Crab {Platymaia wyville-thomsoni). 

 (After Miers.) 



Reduced. 



species of deep-sea animals. There are many 

 examples of this among Crustacea, and they are 

 added to by every deep-sea dredging expedition. 

 For example, the giant Isopod Bathynomus 

 (Plate XVIII.) was first discovered in West Indian 

 seas, and the same species has since been dredged 

 near Ceylon, while a second species has been found 

 off the Japanese coast. Of the strange lobster-like 



