118 
MARINE SHELLS OF WEST COAST OF NORTH AMERICA 
Type in U. S. N. M., No. 253037. Type locality, Central California, 
on Haliotis shells. 
Range. Monterey, California, to Point Abreojos, Lower California. 
Family CHAMID2E 
Genus CHAMA Linnaeus, 1758. 
Shell orbicular, ovate or oblong-ovate, irregular, inequivalve, pro¬ 
fusely ornamented with spines, scales or lamellae; lower valve more or 
less deeply convex, upper valve flatter; umbones unequal distant, involuted 
sometimes to the right, sometimes to the left in the same species. Hinge 
composed of a single thick oblique slightly crenated tooth inserted in a 
correspondingly grooved pit in the opposite valve. Muscular impressions 
two, lateral large. Ligament external, divaricate behind the umbones. 
(Conch. Iconica.) 
Type. Chama lazara Linnaeus. 
Distribution. Tropical seas, especially amongst coral reefs. 
Range in time. Cretaceous, Pleistocene. 
Chama pellucida Sowerby, 1834. 
Proc. Zool. Soc., p. ISO. Keep, West Coast Shells; fig. 155. 
Chama testa alba roseo seu rubro fucata vel strigata, lamellis frequen- 
tibus, frondibus elongatis pellucidis; intus alba, limbo crenulato. (Sow¬ 
erby.) 
Shell orbicular circuitously triangular, affixed by the side, both valves 
very beautifully concentrically lamellated, lamellae small, somewhat erect, 
margins of the valves very minutely crenulated; whitish, peculiarly trans¬ 
parent, rayed from the umbones with scarlet rose. Length, 50; height, 
52; diameter, 38 mm. (Conch. Iconica.) 
Type in Cuming Coll., British Museum. Type locality, Iquique, 
Peru. 
Range. Oregon to Chile and the Galapagos Islands. In the Pleisto¬ 
cene at San Pedro and the Pliocene in Ventura County, California. 
Chama frondosa Broderip, 1834. 
Proc. Zool. Soc., p. 148. Trans. Zool. Soc., 5; pi. 38, figs. 1, 2. 
Chama testa sublobata, lamellosa, lamellis sinuosis frondosis, longitudi- 
naliter plicatis et in utraque valva cardinem versus biseriatis, maximis; 
intus albida, limbo purpurascente, crenulato. (Broderip.) 
Shell ovate or somewhat squarely ovate, more or less lobed, very 
closely irregularly lamellose, lamellae finely radiately plaited, sinuous, in 
two rows, one posterior, the other medial, radiating from the umbone, the 
lamellae are much larger and very beautifully frondose; interiorly the 
