NO. 1222. ISOPODS OF THE ATLANTIC COAST— RICHARDSON. 533 



36. CASSIDINA Milne Edwards. 



87. CASSIDINA LUNIFRONS Richardson. 

 Cassidhui Innifroiiy Richardson, Am. Nat., XXXIV, 1900, \>. 222. 



Body oval, surface smooth. 



Head broader anteriorly than posteriorly, the antero-latoral angles 

 being- produced in a lateral direction and forming- very acute angles. 

 The ej^es are situated at the post-lateral corners 

 of the head. The tirst pair of antennae reach two 

 or three joints beyond the antero-lateral angle of 

 the head; liagellum tive-jointed. The second pair 

 almost reach the posterior margin of the first 

 thoracic segment; flagellum contains about eight 

 joints, the first four being large, the last four 

 small and setose. 



The first thoracic segment is well fitted to the 

 head, so that the elliptical outline of the bod}^ 

 is preserved. The segments are subequal, with 

 straight lateral margins. The epimera are hardly 

 distinct from the segments. 



The first segment of the abdomen is short. ^'''- ''-^toNs.'''^ '™' 

 The terminal segment is subtriangular, with apex 

 truncate. The inner branch of the uropoda is pointed at its extremity, 

 and reaches the tip of the abdomen. The outer branch is rudimen- 

 tary, about one-fourth as long as the inner branch. 



Color, brown. 



Specimens were found at Great Egg Harbor, New Jersey, by Wil- 

 liam Stimpson. 



Type.—OdX. No. 4402, U.S.N. M. 



37. SPH^EROMA Latreille. 



ANALYTICAL KEY TO THE SPECIES OF SPH.EROMA. 



a. Outer branch of the uropoda denticulate on its external margin. 



h. Abdomen without tubercules 88. Splvxromn quadridentntnni Say. 



//. Abdomen with tubercules 89. Spluvronut destruetor Richardson. 



a'. Outer branch of the uropoda smooth on its external magin. 



90. Sphaeroma yucatunum, new species. 



88. SPHiEROMA QUADRIDENTATUM Say. 



Splixroma quad r Ida datum Say, Jour. Acad. Nat. i>ci. I'hila., I, 1818, p. 400. — 

 Harger, Am. Jour. 8ci., V, 1873, p. 314; Report U. S. Commissioner 

 of Fish and Fisheries, 1874, Pt. 1, p. 569 (275), pi. v, tig. 21; Proc. U. S. 

 Nat. Mus., II, 1879, p. 161. — V^errill, Report U. S. Commissioner of Fish 

 and Fisheries, 1874, Pt. 1, p. 315 (21). — Harger, Report U. S. Commis- 

 sioner of Fish and Fisheries, 1880, Pt. 6, pp. 368-370, pi. ix, fig. 53. 



ILthitat. — Provincetown, Massachusetts; Cape Charles City, Vir- 

 ginia; St. Catherine's Island, Georgia; East Florida; Key West, 

 Florida. 



Depth. — Surface to one-half fathom. 



