151 



2188 Psephidia Lordi 



Synonymy: — Chione Lordi Baird, 1863. — Psephis Lordi Cpr. 

 Port Etches, Alaska. — Catalina Island, Cal., in 4-15 fms. 

 White, pale green or straw color, quite trigonal and plump, 

 often containing the nepionic young. 



2189 Psephidia oval is 



"Shell small, white, polished, oval, subcompressed; surface 

 with obsolete concentric threads near the anterior base, but over 

 most of the disk smooth; beaks small and very low, at about the 

 anterior third of the length; lunule elongated, extremely narrow, 

 nearly as long as the anterior dorsal slope; escutcheon linear or 

 none; interior white, the pallial sinus moderate, pointed; inter- 

 nal margin delicately striated; hinge well developed, like that of 

 P. Lordi, with 3 entire cardinals and no anterior lateral tooth. 

 Length 8.5, height 6.5, diam. 3 mm." — Dall, U. S. Natl, mus pr 

 26:407. 



Type locality: — north side of Catalina Island, Cal., in 16 fms. 

 — Bering Sea to San Diego, Cal., in 3-20 fms. 



2190 Gemma gemma Totten, 1834. 

 Variety purpurea H. C. Lea. 1842. 



Cape Cod to the Bahamas. — Texas. — San Francisco, Cal., in- 

 troduced with oysters about 1899. 



More inflated than typical form, trigonal, and with uniform 

 concentric threads sharply defined; color variable. 



Synonymy: — G: concentrica Dall. 1889. 

 o 



2191 Dall, William Healey: 



Synopsis of the family Astartidse, with a review of the Amer- 

 ican species. U. S. nat mus pr 26:933-951, t 62-63. 

 Nos. 2192-2201 are species not already listed. 



2192 Astarte alaskensis 



"Shell ovate, subcompressed, white, with a dark, strong, cadu- 

 cous periostracum, which, like that of A. elliptica, becomes black 

 in the dead or senile shells; valves quite insequilateral, beaks at 

 the anterior third, elevated, slight compressed, prosagyrate; lu- 

 nule excavated, sublanceolate, the escutcheon longer and wider;' 

 sculpture of about a dozen concentric riblets with wider inter- 

 spaces, more feeble near the ventral and posterior margins; inner 

 margins entire, smooth; hinge solid, the teeth narrow and entire. 

 Height 26, length 31.5, diam. 14 mm." — Dall, t 63 f 2. 



Type locality: Unimak Island, in 70 fms. 



2193 Astart polaris 



"Shell rounded-trigonal, moderately thick, bluish white, cov- 

 ered with a slightly polished light-brown periostracum; valves 

 moderately convex, with the umbones high, somewhat prosogy- 

 rate, over a well-impressed lanceolate lunule, which is unequally 

 divided, the right valve bearing the larger share; escutcheon nar- 

 rower and longer than the lunule, impressed, smooth; sculpture of 

 40 or more small, narrow, regular, concentric riblets separated by 

 about equal interspaces; in the adult the posterior slope and ven- 

 tral 3d of the disk have the riblets replaced by somewhat uneven 

 concentric striation; interior smooth, the inner margins finely 

 evenly crenate; hinge rather solid, the middle cardinal in each 

 valve grooved or bifid. Height 25, length 28, diam. 15 mm." — 

 Dall, t 63 f 5. 



Type locality: — Shumagin Islands, Alaska, in 51 fms. Also 

 Greenland. 



