148 AMERICAN JOURNAL 



It is also without the roughened dental process which distin- 

 guishes the genus Mercenaria. 



This species has somewhat the shape, but not the coloration, 

 of V. alboradiata, Sby., from the Gulf of Mexico. The latter is 

 a blunter, rounder shell posteriorly. 



A large worn valve obtained by me at Monterey, but not re- 

 turned by Dr. Carpenter, may have been this species or V. 

 Stimpsoni. It was erroneously referred, in the absence of types, 

 to V. Kennerleyi, Cpr., at that time. 



The dorsal margins of the valves of this species are a little 

 flexuous. 



CARDIIDiE. 



Cardium (? Serripes) La-Perousii, Desh. 



Cardium Laperousii, Desh., Rev. Zool. p. 360, 1839. Mag. 

 Zool. 1840, pi. 48. 



This species appears quite distinct from Serripes gronlandicus, 

 in its much more transverse and equilateral shell. Were there 

 any doubt upon the subject, however, it would be set at rest by 

 the fact that this species has a rounded, geniculate foot, entirely 

 destitute of the serrations which characterize the foot of gron- 

 landicus, and gave the name to the subgenus. 



I dredged it alive at Sitka, in 14 fathoms, mud and shell ; 

 obtained dead valves at Unga, North Harbor, in four fathoms, 

 mud ; on the beach near the mouth of the Avatcha River, Avat- 

 cha Bay, Kamtchatka ; and at Plover Bay, Eastern Siberia, near 

 Bering Strait. 



Cardium Islandicum. 



Very large and fine specimens of this species were obtained at 

 Sitka ; Unga, Kodiak, Unalashka, Tongass, Norton Sound, 

 Plover Bay, Bering Strait, St. George Island and Petropav- 

 loosk, also furnished examples. Cardium Nuttallii, Conrad, 

 (=corbis, Desh., Cpr., not Martyn,) was found at Sitka, Unga, 

 Kodiak and Avatcha Bay. 



Cardium (Serripes) gronlandicum from all of the localities 

 above noted for C. Islandicum, and especially large and fine 

 from Kodiak. Cardium blandum, Gld., was obtained at Sitka 

 and Unalashka. 



CHAMIDiE. 



CHAMA, Liu. 

 ClIAMA inermis, n. s. 



Shell rugged, sinistral, obscurely three sided. Right valve 



