54 



THE LIFE OF CRUSTACEA 



The thoracic limbs, of which the first pair form 

 maxillipeds, have no exopodites, and are partly 

 hidden by a row of shield-like plates along the sides 

 of the thorax. These plates are formed by the 

 IV. v. 



a. 



FIG. 22 Two SPECIES OF CAPRELLIDJE. (From Lankester's 

 "Treatise on Zoology," after Sars.) 



A, Phtisica marina, a species which retains the fourth and fifth pairs 

 of thoracic limbs (prp' y prp") ; B, Caprella linearis, in which these 

 limbs are represented only by the gills (br). (Enlarged.) a', 

 Antennule ; a", antenna ; abd, vestigial abdomen ; gn, gnathopods ; 

 m, brood-pouch ; IV, V, fourth and fifth thoracic somites 



enlarged and flattened basal segments of the limbs 

 themselves, and on the inner side they carry a series 

 of oval plates, which are the gills. The abdominal 



