ISOPODS OF NORTH AMERICA. 241 



and seventh segments together are shorter than the second segment. 

 The hinder corners of the two first segments are nearly rectangular; 

 those of the third and fourth truncated; those of the last three 

 rounded. 



"The epimerals of the second and third segments are broader at the 

 posterior end, bent downward at the anterior. That of the second 

 segment occupies the whole side of the segment; those of the third 

 and fourth segments scarcely more than two-thirds of it; those of the 

 tifth and sixth segments fully thi'ee-fourths of it, and the last one the 

 "yhole of the segment. . The epimerals of the fourth, tifth, and sixth 

 segments are broader at the anterior margin, narrower behind. The 

 last one is oblong, with rounded ends. 



"The first pair of pereiopoda have the tibia broadly extended, the 

 dactylus she rt. The two following pairs are subequal, with the femora 

 nmch longer than broad. The following four pairs have much broader 

 femora and strongly developed carina\ In the seventh pair the femur 

 is as broad as long, the hinder margin is straight. 



"The pleon is as broad at the base as long, the first segment longer 

 than the second, but narrow^er than half of the fifth (2 : 5). The three 

 last pleonal segments are broader than the urus (10 : 9) and a little 

 narrower than the tifth (or fourth) segment of the pereion (10 : 11). 

 The whole pleon equals the fifth pereional segment in length. 



" The urus is broad, nearly semicircular, not (juite twice as broad as 

 long (1) : 5); the uppei- side is perfectly plain and smooth. 



"The pleon and urus together are about a third of the length of the 

 pereion with the head (IS : 51). 



" The uropoda reach a little beyond the posterior margin of the urus. 

 The peduncles are long and stout, nearly as long as the inner ramus 

 (14:17). The inner ramus reaches a little beyond the outer. It is 

 oblong-lanceolate. The exterior one is falciform. 



' *■ Color, bright yellow . 



"Length, 18 mm." — Bovallius." 



MEINERTIA GILBERTI Richardson. 

 Meinertia gilbcrti RicuARDmy, Proc. U. 8. Nat. Mu;^., XXVII, 1904, p. 53. 



Locality. — Mazatlan. 



Parasite of Mugil hospes. 



Head set in first segment of thorax, the antero-lateral prolongations 

 of which extend forward to about the middle of the eye. Shape of the 

 head somewhat triangular; posterior margin straight; anterior margin 

 produced somewhat at the middle, but (^liite rounded. P^j^es very 

 large, far apart, and situated at the sides of the head. First pair of 

 antenna? consist of seven joints and extend to the middle of the eye; 



aBihang till K. Sv. Vet.-Akad. Handl., X, No. 11, 1885, pp. 21-22. 

 28589—05 l(i 



