ACEPHALA. A19 
especially at the anterior end, are raised into delicate, arched, obtuse, 
crowded, somewhat imbricating, concentric ridges, only seen on care- 
ful examination; the grooves are also barred by delicate transverse 
folds. The ribs are not wanting, but almost disappear in front of the 
beaks. Interior with the central portion cream-coloured, margin exte- 
rior to the pallial impression pale clay-colour: internal edge with five 
short crenulations. Hinge delicate. 
Length seven-eighths of an inch; height four-fifths of an inch; 
breadth three-fifths of an inch. 
Inhabits Puget’s Sound, Oregon. 
I at first supposed this to be the young of C. Californianum, but 
on closer examination find that there are about ten more ribs; and the 
sculpture, instead of exhibiting, even in its earliest stages, granules 
along each angle of the ribs, and afterwards coalescing to form a 
transverse varix, is quite different. It seems to be the analogue of 
C. Icelandicum. 'The two ends are very nearly alike, but the whole 
shell varies from circular to transverse oval. ‘The ribs in that are 
acute, and proportionally narrower, and the fringed epidermis is 
peculiar. 
Figures 534, 534 a, lateral and dorsal views of the shell. 
VENUS TOREUMA (Gould). 
Testa ventricosa, subglobosa, viz obliqua, straminea lituris angulatis 
rufis picta, concentrice porcata ; liris numerosis ad latera granulosis, 
acutis, crenulatis ; interstitiis minutissime striatis, et ineols angula- 
tis pallidis quast indentatis ; apicibus submedianis, tumidis, obliquis ; 
lunula profunda, laté cordata: intus pallida; margine crenulato : 
cardo validus ; dente postico valve sinistre longitudinal ; dente an- 
tico bi-ramoso. 
Venus toreuma, Goutp; Proceed. Boston Soc. Nat. Hist., ii. 277. 
July 1850. Expedition Shells, 84. 
SHELL small, subglobose, nearly equilateral, slightly oblique : ante- 
