CHAMA, CARDIUM AND VENUS 69 
trace of purple internally on the upper, posterior 
margin. The hinge-teeth are strong, and the sinus 
deep. This shell sometimes reaches a length of 
nearly five inches. It is found from central Cali- 
fornia to San Diego. 
Saxidémus giganteus, Desh., the Giant Saxi- 
dome, is the other species. It ranges from the 
Aleutian Islands to the Bay of Monterey. It is 
solid, broad and heavy; but the concentric struc- 
ture is much less pronounced than in the last 
species. While the young are yellowish white, 
and the exterior is sometimes fulvous, the interior 
is always white. The adult is said to sometimes 
reach a length of 130 mm. I gathered numerous 
specimens at Sitka, averaging about 3 inches in 
length, and nearly that in height. They were 
