234 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.54. 



VENERICARDIA (CYCLOCARDIA) MORSEI, new species. 



Shell of moderate size, solid, moderately inflated, covered by a 

 yellowish horny periostracum ; the umbones rather acute, prosocoe- 

 lous, over a short, rounded, deeply impressed lunule; sculpture of 

 17-18 radiating arcuate ribs, rendered slightly nodulous in places 

 by rude, conspicuous, rather irregular lines of growth, and separated 

 by subequal, almost channelled, interspaces ; interior yellowish white, 

 the muscular impressions rather deep, the hinge normal, the margin 

 with squarish crenulations ; the ligament as long as the posterior 

 hinge-line. Height of shell 28 ; width 25 ; diameter 15 mm. 



Habitat. — Sagami, Japan. Hirase collection. Cotype, U. S. Nat. 

 Mus. Cat. No. 274075. 



This species has a remarkable superficial resemblance to F. horealis 

 Conrad, of the North Atlantic, and, without careful comparison, 

 would be mihesitatingly referred to that species. The number of rays 

 is the same, the profile is very similar, and the color not very different. 

 However, a close examination shows that in the Japanese species the 

 periostracum is horny, not villous; the lunule is short, rounded and 

 deep, not long, narrow and shallow; the valves are more inflated; 

 the radiating sculpture is more prominent, the interspaces are more 

 sharply defined, and the anterior cardinal tooth averages narrower. 

 The present species is named in honor of Prof. Edward S. Morse, 

 who has published on this genus. There is no closely related species 

 on the Pacific roast of America. 



VENERICARDIA HIRASEI, new species. 



Shell solid, subquadrate, suffused with light brown and rose color, 

 inflated, equivalve, inequilateral, the beaks high, strongly incurved, 

 prosocoelous ; umbones one-sixth the total length from the anterior 

 end, overhanging a deeply impressed short-cordate unsculptured 

 lunule; radial sculpture of 29-30 narrow prominent equal and equally 

 distributed ribs with subequal channelled interspaces; these ribs are 

 spinose with each spine issuing from the interior of its predecessor, 

 the distal margin of the cup of each spine in the middle part of 

 the disk being thickened into a conspicuous ring out of which the 

 next spine issues, as in some Cardiums; in the middle of the shell 

 there are about four spines to the length of five millimeters along the 

 rib ; interior white, the hinge normal, the lower valve-margin crenate 

 by the sculpture. Length of shell 37 ; height 30 ; diameter 30 mm. 



Habitat. — Kii, Japan. Hirase collection. 



This very handsome Venericardia has no very close relatives in the 

 genus, perhaps the V. spinosa Lamarck of the Mediterranean being 

 as near as any. There is nothing like it on the Pacific coast of 

 America. 



