CLASS PELECYPODA 
153 
Saxidomus giganteus Deshayes, 1839. 
Revue Zool. Soc. Cuwerienne, p. 350. Guerin, Mag. de Zool. Moll., 1841, pi. 43. 
Shell solid, broad, and heavy; the young are yellowish white; the 
adult attains a length of 130 mm., and the concentric sculpture is much 
less pronounced than in 5. nuttallii. The exterior is sometimes fulvus, but 
the interior is always white. Specimens which have nestled in rock crevices 
are usually stunted and distorted. (Dali.) 
Type locality, not known. 
Range. Aleutian Islands, from Attu eastward and south to Mon¬ 
terey, California. 
Saxidomus giganteus brevis Dali, 1916. 
Proc. U. S. N. M., 52 :413. 
Shell short, subtriangular, small in comparison with the type and much 
less elongated. Length, 60; height, 50; diameter, 33 mm. (Dali.) 
Type in U. S. N. M., No. 204020. Type locality, Mole Harbor, Ad¬ 
miralty Islands, Alaska. 
Range. Admiralty Islands, Alaska to Tacoma, Washington. 
Genus CHIONE Megerle, 1811. 
Shell oval, triangular or subcordiform; margins finely crenulated; 
hinge narrow, solid, with three teeth in the right valve and two in the 
left, the anterior tooth longest; ligament narrow; pallial sinus shallow. 
Mantle-margins folded and dentate; siphons short, unequal, the branchial 
doubly cirrated, the anal ciliated. (Tryon. S. S. Conch.) 
Type. Venus cancellata Linn. 
Distribution. World wide. 
Range in Time. Pleistocene, Pliocene, Miocene. 
Chione fluctifraga Sowerby, 1853. 
Plate 39, fig. 3. 
Thes. Conch., Venus, p. 712; pi. 154, figs. 42, 43. 
V. testa ponderosa, suboblique rotundata, alba, concentrice purpureo 
distanter fasciata, costellis radiantibus postice et antice majoribus et 
costellis interruptim fluctuatis intersecta; latere postico subangulato; 
margine dorsali rotundato, subarcuato, maculato, paululum depresso; 
margine ventrali intus crenulato, purpureo. (Sowerby.) 
Named as above from the character of the concentric ridges, which 
are fluctuated and as it were broken up on the surface; the shell is solid, 
rounded, and nearly white, with several bands of livid colour; the inside 
is purple at the border, and about the posterior impressions. Length, 25; 
height, 21; diameter, 15 mm. (Sowerby.) 
