ISOPODS OF NORTH AMERICA. 



185 



and both are pointed at the pot^terior extremity. The inner branch is 

 ver}" slig-htl}" excavate on the exterior margin about 1 mm. from the 

 extremity. Both branches are denticulate and furnished with spines. 

 The first three pairs of leofs are prehensile, the last four pairs 

 and)ulatory. All the legs are very slender and free from spines. 



JEGA SYMMETRICA Richardson. 

 jEga symmetrica Rr'hakdsox, Bull. V. S. Fish ('Omiii., XXIV, 1905, pp. 211-212. 



Localities. — Vicinity of Nahii Bay, Behm Canal, southeast Alaska; 



Queen Charlotte Sound, oti' Fort Kupert, Vancouver 



Island, British Columbia. 



Bod}" ovate, twice as h)no- as ])road. Color yellow. 



denseh' covered with liij;ht-l)rowni dots, which form 



a regular line along the mai'gin of each segment. 



Surface smooth. Head with frontal margin pro- 

 duced in a median point, which arches over the basal 



joints of the antennaB and meets the frontal lamina 



or interantennal plate on the underside. The e3'es 



are narrow and elongate, composed of muiierous 



ocelli. They are separated in front ))y a distance 



equal to the length of one eye. The tirst pair of 



antennie extend to the posterior margin of tiie tirst 



thoracic segment; the joints of the peduncle are not 



dilated, although the fii'st tAvo joints are somewhat 



wider than the third, nor is there a process at the distal extremity 



of the second joint. The first two joints 

 are of equal length; the third is as long- 

 as the first two together; the llagellum is 

 composed of eleven joints. The second 

 pair of antenna^ reach the middle of the 

 third thoracic segment; the flagellum is 

 composed of sixteen joints. The frontal 

 lamina or interantennal plate is conical, 

 with the distal end fiat, the proximal end 

 produced to an acute point. 



The several seguKMits of the thorax are 

 about equal in length, the hist one being 

 slightl}^ shorter. The epimera are large, 

 su])(|uadrate, with the outer distal angle 



of the last three produced posteriorly be3'ond the margin of their 



respective segments. 

 The first three pairs of legs have the propodus l)eset with three 



small spines along the inner margin; the carpus is short and armed 



with one spine; the merus is pio\ided with five spines and the ischium 



Fig. 1(59. — ^Ega sym- 

 metrica. X 2*. 



Fig. 170. — ^ga symmetrica, a, Maxil- 

 i.iPEi). X 27^. 6, Palpofsame. x 51|. 



