ISOPODS OF NORTH AMEEICA. 287 



segment is about equal in length to the last thoracic segment, and is 

 marked on. either side by two suture lines indicative of coalesced seg- 

 ments. The terminal segment is entire, and not produced, being 

 evenly rounded in outline. The anterior portion of the segment is 

 convex, with a longitudinal series of four small tubercles on either 

 side of the median line, the two series being close together. The pos- 

 terior extremity of the segment is marked by a prominent transverse 

 elevation. 



The inner immovable branch of the uropoda is narrow, elongate, 

 and pointed posteriorly; it extends to the extremit} 7 of the abdomen. 

 The outer mobile branch is provided on the lateral margin with five 

 strong teeth. Both branches are of equal length. 



The first three pairs of legs are slender, and are furnished with long 

 hairs. The other four pairs are somewhat 

 stouter. 



Ten specimens were collected at Sausa- 

 lito, California, by Dr. Bitter and party. 



This species is perhaps more closely al- 

 lied to Sphseroma sieboldii Dollfus 05 from 

 Japan than it is to any of the known spe- 

 cies of the genus from the Pacific coast of 

 North America. It differs, however, from 

 that species in having a prominent trans- FIG - SOO.-SPH^ROMA PENTODON. 



L , . , . . ,, ABDOMEN, x 8. 



verse elevation on the posterior portion 01 



the terminal segment, while in S. sieboldii the posterior part of the 

 segment is distinctly concave; in having five teeth on the lateral mar- 

 gin of the outer uropod, while in S. sieboldii there are seven; in hav- 

 ing fifteen joints to the flagellum of the second pair of antennae, while 

 this organ in S. sieboldii has a flagellum composed of only ten joints; 

 in having two longitudinal series of four small tubercles, one on either 

 side of the median line on the terminal abdominal segment, while in 

 S. sieboldii the granulations on the caudal segment form, in the middle, 

 two divergent lines; and in having the body covered with minute gran- 

 ulations, while in S. sieboldii the granulations are strong and more 

 prominent. 



The type is in the Museum of the University of California. The 

 cotype is in the U. 8. National Museum, Cat. No. 28768. 



49. Genus EXOSPH^EROMA Stebbing. 



Second, third, and fourth articles of the palp of the uiaxillipeds 

 produced into lobes. 



The outer branch of the uropoda is not denticulate on the exterior 

 margin. 



Characters otherwise as in the genus Sphseroma Latreille. 



a Notes from the Levden Museum, XI, 1889, pp. 93, 94, pi. v. 



