and Shells of Massachusetts Bay. 83 
tions, at their insertions, but minutely crenulated on their 
interior margin ; terminal valves semilunate, margin mem- 
branous, ash colored, covered with fine granule, and 
having a narrow, black line, surrounding it in the middle ; 
internal color a dull white. 
Oxservations. This species was obtained from the 
stomachs of fishes, in various parts of our outer Bay, 
between Cohasset rocks and Cape Ann. 
It is much smaller than the preceding species, and ap- 
parently not quite so common. The granose margin 
prevents its ever being confounded with that, although 
in other respects, they sometimes are considerably alike. 
But few specimens, even in tolerably perfect condition, 
were met with, as the farinaceous substance coating the 
shell, was very easily rubbed off, in which state, the 
granulated appearance of the valves is much more con- 
spicuous than when perfect. 
The only species I am aware of, having much analogy 
to this, is C. minimus, Lin., described by him as ** smooth, 
black, sprinkled with meal in patches, half an inch long,” 
inhabiting the seas of Norway, and figured by Chemnitz, 
vol. 8, pl. 96, fig. 814. 
Curiron Emersonut. 
Plate III. fig. 10. 
C. testà ovali, anticé paulum compressa, àlbidà, membrana squal 
Pubescente tectà, valvis posticé arcuatis, lateribus rotundatis, areis 
carinatà ab apice ad latus posticum veia decurrente; margine 
ciculis crinitis, ordinibus binis dispositis. 
Long. sixteen twentieths, lat. ten twentieths, of an 
inch. 
