NO. 1175. ISOPODS OF THE PACIFIC COAST— RICHARDSON. 835 



13. SPH^EROMA Latreille. 



ANALYTICAL KEY TO THE SPECIES OF SPHyEUOMA. 



a. Body widening gradually from head backwards. Thorax transversely ridged 

 and provided with three longitudinal rows of small tubercles. Branches of 



the uropoda very large, expanded 25. Spharovia amplicauda Stimpson. 



a' . Body not increasing in width. Surface of thorax smooth. Branches of the 

 uropoda not expanded. 

 /). Extremity of abdomen produced in a rhomboid process. 



26. Splwroma rhomburiim, new si)ecies. 

 b'. Extremity of abdomen not produced. 



c. Surface of abdomen tubercular 27. Sphwroma octoncum, new species. 



c'. Surface of abdomen smooth 28. Sphcerovia oregonensis Dana. 



25. SPHiEROMA AMPLICAUDA Stimpson. 

 Spharoma amplicauda Stimpson, Proc. Bos. Soc. Nat. Hist.. VI, 1857, p. 89. 

 Habitat. — Tomales Bay, California. 



Stebbing ' suggests that a new genus near Cycloidura may be required 

 for this species. 



26. SPHiEROMA RHOMBURUM, new species. 



Surface of body punctate; color, whitish yellow. 



Head small. First pair of antenme reach almost to the x)osterior 

 margin of the first thoracic segment. Second pair 

 of antennfB extend quite to the posterior margin 

 of the first thoracic segment. Eyes situated j)ost- 

 laterally. 



Thoracic segments equal in length. Epimera 

 broad and short, extending downwards, forming 

 an angle with the segments. 



First abdominal segment as long as any of the ^^^- 12. — sph^eoma 

 thoracic segments, crossed by suture lines and ABDmrEN'!''" "" "*' 

 surmounted by two tubercles, close together, one on 

 either side of the median line. Terminal segment with its extremity 

 produced in a process rhomboid in shape, and with sides infolded, 

 forming a kind of funnel-like opening when seen from beneath. At 

 the base of this segment are two tubercles, which are continuous with 

 two longitudinal ridges in the center of the segment. These ridges 

 unite near the extremity, and continue as one median ridge. The uro- 

 poda are shorter than the terminal segment; the outer branch is more 

 lanceolate in shape; both are of equal length. 



Two specimens were taken at Monterey Bay, California, by Mr. 

 Heath. 



Typc.—^o. 22573, U.S.N.M. 



This species is near S. egregium Chilton^ from Akaroa, but differs in 



' Hist. Crust., 1893, p. 36-1. 



2 Trans. New Zealand Inst., XXIV, 1891, p. 269. 



