CHAMA, CARDIUM AND VENUS 79 



The Saxidomes of this coast have recently been 

 revised by Dr. Dall, and the numerous names re- 

 duced to two. The hrst is Saxidomi/s nuttaUif^ 

 Conr., Nuttall's Saxidome, a good likeness of which 

 is shown in Figure 53. It includes the old ^. aratus, 

 Gld. The shells are usually marked by rough, con- 

 centric ridges, as shown in the hgure. When young, 

 there are brownish markings near the beaks, with 

 a 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 hve inches. It is found from central Cali- 

 fornia to San Diego. 



Saxidotnus giganteus, Desh., the Giant Saxidome, 

 is the other species. It ranges from the Aleutian 

 Islands to the Bay of Monterey. It is solid, broad 

 and heavy, but the concentric structure is much less 

 pronounced than in the last species. While the 

 young are yellowish white, and the exterior of older 

 specimens is sometimes fulvous, the interior is always 

 white. The adult shell is said to sometimes reach 

 a length of five inches. I gathered numerous speci- 

 mens at Sitka, averaging about 3 inches in length 

 and nearly that in height. They were pure white 

 inside, and almost glossy, while externally they were 

 comparatively smooth and quite chalky. This shell 

 has been confounded with Saxidomus squalid us, but 

 that species is found on the coast of South America. 

 The Giant Saxidomes are sometimes sold in the 

 markets of Portland, Ore., being brought up from 

 the coast. 



There are three species of Chione upon the coast. 



