ISOPODS OF NORTH AMERICA. 



531 



The pleopoda are five pairs of large, ))road, smooth, leaf-like, 

 double-branched appendages not cf)ncealed on the dorsal side by the 

 small opimeral plates of the al)d()minal segments, 

 from which they project in full view. The uropoda 

 are a pair of single-branched, simple appendages, 

 similar in shape to the branches of the pleopoda. 



The marsupium is formed of five pairs of incuba- 

 tory lamella?, which overlap so as to completely 

 encompass the ventral surface of the body; the first 

 pair have the terminal lobe of the distal segment 

 small, but well defined. 



There are seven pairs of small legs, all similar in 

 size and structure; a high triangularly shaped ex- 

 pansion or carina is present on the basis. 



Color uniforndy light 3'ellow. 



Mal(% two and one-third times longer than 

 broad, with all seven segments of the thorax and 

 all six segments of the abdomen distinct. Eyes 

 present. Abdomen occupies one-fourth of the 

 entire length of the bod}'. 



Only one specimen was found at Ke}" West by Henry Hemphill 

 Pai'asitic oa PHrolixtJies scj'sjji/iosn.s (Gibbes). 



Ti/pe.—Cat. No. 29(>9i, U.S.N.M. 



Fig. 577.— Pseudione 

 cuRTATA. Male, x 

 23. 



88. Genus STEGOPHRYXUS Thompson.« 



Branchia 1 parasites. 



Female with the sixth segment of the thorax greatly longer than an}' 

 of the other segments. 



Alxlomen with all six segments distinct; lateral parts or pleural 

 lamelhv not developed. 



There are five pairs of tri-ramous pleopods. 



Uropoda consist of a pair of small, rounded, oval bodies, between 

 which is a small conical process. 



Male with all the segments of the thorax distinct. 



Abdomen ovoid, without appendages or traces of segmentation. 



a See Thompson for characters of genus, Bull. U. S. Fish Comm., XXI, 1902, p. 56. 



