ISOPODA. 



307 



in many forms, carries unjointed 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 



IV;. 147.— A, male of an Entoniscid (Cancrion miser). B, young larva of an Entoniscid 

 (Portunion muenadis), after Giard and Bonnier, from Lang's Text-book, a', first antenna ; 

 a", second antenna ; ab, abdomen ; au, eye ; h, testis ; he, heart ; I, hepatic tubes ; pl^pl^, 

 the six pleopoda ; ?•, 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 in t lie 

 Entoniscidac, which, as has been confirmed by the recent researches of Giaud 

 and Bonnier (No. 167), are very closely related to the Bopyrvlae. These 



