ISOPODS OF NORTH AMERICA. 



183 



FIG. 166. JGA ARCTICA. a, LEG OF SECOND PAIR, x 27$. 

 b, MAXILLIPED. x 15}. 



The first three segments of the thorax are subequal, each being 3 

 mm. long. The fourth and seventh are subequal, and each is 3 mm. 

 in length. The fifth and sixth are each 4 mm. in length. The epimera 

 are distinctly separated on all the segments with the exception of the 

 first. They are broad plates, with the outer post-lateral angles of 

 the first two and the last two 

 acute. All are crossed ob- 

 liquely by an arched carina. 



All six segments of the 

 abdomen are distinct. The 

 sixth or terminal segment is 

 rounded posteriorly, with a 

 small round median notch. 

 The uropoda do not extend 

 beyond the extremity of the 

 terminal abdominal segment. 

 Both branches are of equal 

 length. The inner one is a 

 little wider than the outer branch. The margins are entire and cren- 

 ulate, and furnished with spines. The outer post-lateral angle of 

 both branches terminates in two small points. 



The first three pairs of legs are prehensile; the last four pairs are 

 ambulatory. The merus of the first three pairs is armed with one 

 large and one small spine, the carpus with one large and three small 

 spines. 



JEGA GRACILIPES Hansen. 



JEga gradlipes HANSEN, Isopoden, Cumaceen und Stomatopoden der Plankton 

 Expedition, 1895, pp. 15-16, pi. i, figs. 6-6c. RICHARDSON, Proc. U. S. Nat. 

 Mus., XXIII, 1901, p. 523. 



Localities. Gulf of Mexico; North Atlantic, latitude 59 north, 

 longitude 8.5 west. 



Depth. 730 fathoms; 1,524 meters (Hansen). 



Body ovate, about twice as long as wide, 11 mm. : 21 mm. 



Head with the anterior margin widely rounded, and produced in a 

 narrow process, which arches over the antennae, separating the basal 

 articles, and meets the small frontal lamina on the other side. The 

 eyes are large, oblong, composite, and occupy almost all of the dorsal 

 surface of the head, extending from the lateral angles along the ante- 

 rior margin and almost meeting in the median line. The first two 

 articles of the first pair of antennae are subequal; the third is nearly 

 three times as long as the second. The flagellum is composed of 

 eighteen articles. The first antennae extend a little beyond the pos- 

 terior margin of the first thoracic segment. The first two articles of 

 the second antennae are subequal; the third is a little longer than the 



