54 



THE LIFE OF CRUSTACEA 



The thoracic limbs, of which the first pair form 

 maxilHpeds, 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. 



Fig. 22 — Two Species of Caprellid^. (From Lankester's 

 " Treatise on Zoology," after Sars.) 



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

 of thoracic limbs {j>rp\ 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 ; 

 tn, 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 



