CLASS PELECYPODA 
119 
edges of the valves are very minutely crenulated and wrinkled with striae; 
bright saffron yellow, stained here and there with purple, interior bluish 
white, stained with rich crimson purple toward the edge. (Conch. Iconica.) 
Type in Cuming Coll., British Museum. Type locality, Island La 
Plata, West Colombia. 
Range. San Diego, California, to Peru. 
Chama buddiana C. B. Adams, 1850. 
Panama Shells, p. 253. 
Shell orbicular or subtriangular; exterior surface and inner margins 
purplish red, with the spines pure white ,* surface uneven, with interrupted 
radiating striae; upper valve ornamented with a few radiating series of 
short thick triangular vaulted spines; lower valve attached by about two- 
thirds to three-quarters of its surface, the rest being like the upper valve, 
but with the dentiform spines smaller; within both valves are deeply and 
finely crenulated at the junction of the white surface and red margin; 
beaks submarginal. Easily distinguished from C. paciiica and C. broderipii 
by the small thick dentiform triangular white spines. Diameter about 
3 inches. (C. B. Adams.) 
Type in Amherst College Collection. Type locality, Guaymas, Mexico. 
Range. Monterey, California, to Panama. 
Chama exogyra Conrad, 1837. 
Jour. Acad. Nat. Sci., Phila., 7:256. Conch. Iconica, Chatna, pi. 7; fig. 38. 
Shell obliquely affixed, sinistral; lamellae of the valves prominent, 
deeply lobed; color white, tinged with red and green; within white, 
margin entire; posterior muscular impression profoundly elongated. 
(Conrad.) 
Type in Acad. Nat. Sci. Phila.? Type locality near Santa Barbara, 
California. 
Range. Oregon to Panama. In the Pleistocene at Santa Barbara, 
San Pedro, and on San Nicolas Island, California. 
Family THYASIRIDiE 
Genus THYASIRA (Leach) Lamarck, 1818. 
Shell globular, posterior side furrowed or angulated; umbones much 
recurved; lunule short or indistinct; ligament usually and to a certain 
extent external, placed in a groove on the hinge line, and outside the 
hinge plate; teeth altogether wanting. 
The largest known species is the Thyasira bisecta of Conrad from the 
Miocene of the Pacific Coast, which has survived in the deeper water of 
Puget Sound until the present day. (Dali.) 
Type. Tellina flexuosa Montagu. 
