ISOPODS OF NORTH AMERICA. 



479 



ing ones small, the last fringed with hairs. The second pair of anten- 

 nae have a rudimentary flagellum, consisting of five or six joints; the 

 peduncle has the third and fifth joints long and oval in shape, the 

 fourth joint somewhat triangular. 



The thoracic segments are loosely articulated. The lateral mar- 

 gins are straight, with no indication of 

 epimera. 



The terminal segment of the body is 

 rounded in outline, the posterior margin 

 excavated at the insertion of the uropoda, 

 which do not extend beyond the edge of 

 the segment, thus preserving the oval 

 outline. Between the uropoda there is 

 an acute median projection. 



The legs are all simple, with bi-unguic- 

 ulate dactyli. 



One specimen was collected by Prof-. 

 A. E. Verrill and party at the Bermudas, 

 and another by Dr. G. B. Goode, from 

 the same locality. 



Type specimens in Peabody Museum, 

 Yale University. Cat, No. 3251. 



Six species of this genus have been 

 heretofore described: Jseropsis lobata 

 Koehler, Jseropsis marionis Beddard, 

 Jseropsis neo-zealandica Chilton, Jseropsis 



lobata Richardson, Jseropsis dollfusi Norman, and Jseropsis curmcornis 

 (Nicolet). a The present species adds another to the above list. 



It is named in honor of Miss Mary J. Rathbun. 



Family XVIII. MUNNID^E. 6 



Body ovate, short and stout, with the three posterior segments of 

 the thorax sharply marked off from the four anterior ones and much 

 smaller, and gradually becoming narrower. Terminal segment of 

 body vaulted above, subpyriform. 



Eyes, when present, placed on the tips of lateral peduncle-like pro- 

 jections of the head. First pair of antennae placed widely apart, with 

 the flagellum multi-articulate. Second pair of antennae without scale. 



First pair of legs much shorter than the following pairs and pre- 

 hensile. Succeeding pairs more or less rapidly increasing in length, 

 simple, ambulatory. Uropoda small, somewhat separated. 



Pleopoda as in the Janiridse. 



a Jura curvicornis Nicolet, in Gay's Hist, de Chile, III, 1849, p. 263, Zool. Atlas, 

 Crust., No. 3, fig. 10. This species should be referred to the genus Jseropsis. 

 & See Sars for characters of family, Crust, of Norway, II, 1899, p. 105. 



FIG. 537. J.EROPSIS RATHBUN.E. a, 

 HEAD AND FIRST THORACIC SEGMENT. 

 6, MAXILLIPED. c, TERMINAL SEG- 

 MENT AND UROPODA. d, MANDIBLE. 



e, MANDIBLE (ANOTHER VIEW). 



