NOTES ON CYTHEREA (TIVELA) CRASSATELLOIDES CON- 

 RAD, WITH DESCRIPTIONS OF MANY VARIETIES. 



By Robert E. C. Stearns, 



Honorary Associate in Zooloiiy. 



The quahog or hard-shell clarn, Venus mereenaria, of the Atlantic 

 coast of the United States is probably the largest, most solid aud 

 heavy of any of the species of the Yeneridae. The southern form, known 

 as variety wior^owi Conrad, freciuently attains the weight of between three 

 and four pounds, exclusive of the soft parts. Many specimens of these 

 solid fellows were collected in Tampa Bay in January to March, 1869, 

 by Colonel Jewett, Dr. Stimpson, and myself. 



The next representative of the Vcneridde in the matters of size and 

 weight is Tivela crassatelloidefij of the; west coast. The geographical 

 range of this latter species extends from Balleuas Bay, Lower Cali- 

 fornia (Albatross), N. latitude 26° 45', northerly to Santa Cruz in Cali- 

 fornia proper, as reported. It is abundant in Moro Bay, north of Point 

 Con('epcion, and common at Santa Monica and Long Beach in Los 

 Angeles County, on the outer shore of the Coronado peninsula, San 

 Diego, and at many other localities between the limits first indicated. 

 It is at the present time the commonest clam in the Los Angeles 

 markets, which are supplied principally from Santa Monica aud Long 

 Beach. It frequently measures 6 inches in length (anterior to posterior 

 margins), and reaches a weight of nearly 2 pounds. As an article of 

 food I regard it as the best of the so called clams that are found along 

 this part of the coast. Its favorite station is at the lowest tide marks, 

 and it seems to prefer a clean sand to sandy mud or muddy sand 

 between ordinary tide marks, where the other jjrincipal clams of the Los 

 Angeles markets are found, namely, Taj^es diversa, Ghione simiUima, and 

 G. succincta. 



Tivela crassatelloides was described by Conrad' as Trigona crassa- 

 teUoides. It is the Pachydesma of Carpenter's British Association 

 report and, until recently, of California authors. 



In Reeve's Conch. Iconica,- Gytherea crassatelloides, it is described, 

 probably quoting Conrad, as follows : 



Shell obliquely ovate, rather obloug, luothrately triangular, thick, heavy, ventri- 

 cose, covered vsrith a thick horny epidermis, cream color, rayed with purple-violet. 



1 Jour. Acad. Nat. His. Sci. Phila., 1837, VII, p. 253, pi. xix, fig. 17. 



2 Volume XIV, 1864, pi. i. 



Proceedings U. S. National Museum, Vol. XXI— No. 1 149. 



371 



