THE ISOPODA 



215 



niscan stage before sexual maturity is reached. The male (Fig. 

 129, A) develops to the bopyroid stage ("stade bopyrien," Bonnier), 

 characterised by the reduction in size of most of the appendages ; 

 antennules and antennae lose their sensory filaments and become 

 almost vestigial, the thoracic legs are shorter and without coxal 

 plates, the pleopods are greatly reduced, without natatory setae, 

 and the eyes are lost or persist only as pigment-spots. The young 



FIG. 120. 



A, male of Cancrion m iser (Entoniscidae). B, larva of Portunlon maenadis (Entoniscidae) in 

 epicarid stage. a lt antennule ; 03, antenna ; ab, abdomen ; au, eye : h, testis ; he, heart ; I, 

 hepatic caeca ; pli-pl K , the six pairs of abdominal appendages ; r," oral cone ; t^-t 7 , second to 

 seventh pairs of thoracic appendages (the eighth pair are undeveloped at this stage) ; th, thorax. 

 (After Giard and Bonnier, from Korschelt and Heider's Embryology.) 



post-larval female is generally similar to the male, so that we may 

 speak of a bopyroid stage in both sexes, but the adult female is 

 usually much modified, often asymmetrical and distorted by the 

 great development of ovaries and brood-pouch (Fig. 130). The 

 male is often found attached, like a parasite, to the body of the 

 much larger female (Fig. 124, B). 



