AL8 MOLLUSCA. 
crossed by numerous inconspicuous, nodular, concentric bars, most dis- 
tinct about the umbones, covered with a rusty-brown, velvety epider- 
mis, the pile set in radiating ranges, especially in the intercostal spaces. 
Hinge of the right valve with a strong, elevated, oblique, triangu- 
lar tooth, defined by deep furrows each side, its apex detached from 
the margin of the shell, acute ; marginal crenulations deep, well de- 
fined. 
Length three-fourths of an inch; height five-eighths of an inch; 
breadth half an inch. 
Inhabits Puget Sound, Oregon. 
Compared with C. borealis, Conr., it is thicker, less transverse, more 
tumid at the beaks, which are less recurved; the ribs are barred; the 
cardinal tooth is short, triangular (not long faleate) and detached from 
the margin; the crenulations of the margin deeper. 
Figures 532, 532, lateral and dorsal views of the shell. 
CaRDIUM BLANDUM (Gould). 
Testa parva, tenuis, subcircularis, vix transversa, ventricosa, postice 
subtruncata, cinereo-rufescens, costis planulatis radiantibus ad quad- 
riginta insculpta, sulco angusto sejunctis, et liris concentricis tenuisst- 
mis, arcuatis, reflexis, decussatis : apicibus medianis, tumidis, denu- 
datis, eburneis: cavositas albida; margine interno crenulato ; cardine 
debit. 
Cardium blandum, Govutp; Proceed. Boston Soc. Nat. Hist., 1. 
276. Expedition Shells, 83. 
SHELL small, thin, ventricose, equilateral, subcircular, or a little 
transversely oval, yellowish-white, with a thin, closely adhering, fawn- 
coloured epidermis; posterior umbonal slope a little angular, and pos- 
terior tip a little truncated: beaks prominent, acute, incurved or 
slightly antrorse: surface sculptured with upwards of forty radiating 
ribs, separated by narrow grooves; the ribs have the presenting sur- 
face flattened, which, however, at the later stages of growth, and 

