68 



THE LIFE OF CRUSTACEA 



As an example of the larval history of the higher 

 Crustacea, we may take the case of the Common 

 Shore Crab, Carcinus mcenas (Fig. 25). The young 

 stages are common in tow-net gatherings round the 



Pjq_ 25 Larval Stages of the Common Shore Crab {Cavcinus 



jn^rnas—s-E-E Plate IX.). (Partly after Williamson.) 



A, Young zoea, shortly after hatching ; B, megalopa stage ; 

 C, young Crab. A x 20, B and C x 10 



British coasts in the summer-time. The youngest 

 larvse (Fig. 25, A) are translucent little creatures 

 about one-twentieth of an inch long. They have 

 the head and front part of the body covered by a . 

 helmet-shaped carapace, with a long spine standing j 



