ISOPODS OF NORTH AMERICA. 



255 



clos of the tirst pair of anteunio are widely separated, heino- neai-ly 

 2 mm. apart. The maxillipeds have a palp of two articles. The palp 

 of the mandibles is composed of three artick's. 



The first seg-meut of the thorax is about twice as long- as any of the 

 three following segments, which are subecpial. The antcro-hiteral 

 expansions of the first segment are half as wide as the head, 3 mm. in 

 width, and the}'^ are widely rounded at the anterior extremity. The 

 fifth and sixth segments are half as wide in tiu^ median longitudinal 

 line as any of the three preceding segments. Tlu^ seventh segment is 

 a little shorter than the sixth. The epimera are distinctly separated 



Fig. 263. — Cymothoa (istritm (After Schicedte and Meinert). a, Young of the second stage 



(ENLARGED), b, VOlTXc; OF THE FIRST STAGE (ENLARGED). C, LATERAL VIEW OF THORAX OF ADULT 

 FEMALE (REDUCED), (l, .\DULT MALE (ENLARGED), r, ADULT FEMALE (REDI'CED). /, .VDULT FE.MALE 

 (REDUCED). 



on all the segments with the exception of the first. They are narrow 

 plates, extending- or nearl}' extending the full length of the segments. 

 Those of the second segment are a little broader anteriorly than are 

 the others. 



The abdomen is deeply set in the thorax. All the segments are dis- 

 tinct, the lateral parts of the first two being covered by the seventh 

 thoracic segment, so that these segments appear abruptly narrower 

 than the thorax. The following segments gradually increase in width. 

 The sixth or terminal segment is twice as broad as long. ♦> nuu. : 1^ 



