No.isoo. NATURAL HISTORY OF THE ISOPODA— RICHARDSON. 



47 



Fig. 23. — Abdomex and last 

 two thoracic segments 

 ofSph.kroma kEIROL^VIS, 

 new species. x 8. 



Family SPH.EROMID.E. 



SPHiEROMA RETROLiEVIS, new species. 



Bod\' somewhat convex. Head large with eyes post-laterally situated. 

 Segments of thorax subequal with exception of last one, which is shorter 

 than an}' of the others. The epimera are drawn out into narrow proc- 

 esses at the sides of the sog-nients. The epimera. however, are not 

 distinct from the segments, but are consolidated Avith them. The 

 last two segments of the thorax are provided on the posterior niiirgin 

 with four low tubercles in a transverse row, the two on either side of 

 the median line being more prominent than the others. The whole 

 surface of the abdomen is rugose. The first seg- 

 ment has a transverse row of four tul)ercles. The 

 terminal segment is posteriori truncate; the 

 posterior portion is rather fiat on the dorsal sur- 

 face and is unarmed; the more convex anterior 

 portion is provided with two longitudinal rows 

 of three low tubercles on either side of the median 

 line, the middle tubercle in each row being the 

 most prominent; on either side of these two 

 median rows of tubercles are two small tubercles 

 also in longitudinal series. The uropoda do not 

 extend beyond the extremity of the terminal 

 abdominal segment. The inner branch is smooth on both margins; in 

 shape it is long and narrow, and pointed posteriorly. The outer branch 

 is similar in size and shape to the inner branch, but is denticulate on 

 the exterior margin, being armed with four teeth. The legs are in two 

 series. The first three pairs are very slender and feeble and are directed 

 forward. The last four are more robust. Only one specimen was 

 found at Nagasaki, Hizen, Japan, collected b}' Jordan and Snvder. 



Ty2)e.~OAt. No. 28965, U.S.N.M. 



VALVIFERA or IDOTEOIDEA. 



Family IDOTEID^E. 



IDOTEA JAPONICA Richardson. 



7rfo/mja/)on»>a Richardson, Proc. U. S. Nat. Mu.«cum, XXTT, 1900, pp. l,'il-184. 



Locality. — Tokyo, Japan; Moroi'an, Hokkaida, Jajjan. Hakodate, 

 Hokkaido, Japan. (Collected by Jordan and Snyder.) 



PENTIAS, new genus. 

 PENTIAS HAYI, new species. 



Body narrow elongate, four and a half times longer than wide; 

 surface smooth; color in alcohol almost white. 



