ISOPODA. 



307 



in many forms, carries iinjointed tubes or lamellae corresponding in 

 position to the pleopoda ; these are, perhaps, of importance as 

 respiratory organs, and were formerly repeatedly claimed as trans- 

 formed pleopoda. Kossmann, however, has pointed out that they 

 appear as new structures only after the entire disappearance of the 



n 





m$^~-^'' 



Fig. 147.—^, male of an Entoniscid {Cancrion miser). B, young larva of an Entoniscid 

 (Portunion maenadis), after Gtard and Bonnier, from Lang's Texl-hool: a', first antenna ; 

 a", second antenna; ob, abdomen; an, eye; h, testis; he, heart; /, liepatic, tubes; 'j>h~Ph< 

 the six pleopoda ; r, rostrum ; t„-t-, the second to the seventh thoracic limb ; th, thorax. 



latter. This, however, does not disprove the pleopodan character 

 of these appendages, since individual appendages often completely 

 degenerate in the metamorphosis of the Crustacea, and reappear 

 again later. 



The most marked parasitic transformations of the female are found iu the 

 EiUoniscidac, which, as has lieen coiitirmed by the recent researches of Giakd 

 <ind Bonnier (No. 167), are very closely related to the Bopjridae. Tliese 



