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Rh other to form a knobby, cancellate pattern. Dredged occasionally off the Miami area in 35 to 90 fathoms.

$1/3$ inch in length, thin, very delicate. Anal slit in the middle of the anterior slope of the shell and arrow-shaped. Base elongate-oval. Shell $1/3$ high as long. Sculpture of fine cancellations. Margin finely crenulate. Color translucent-white to cream or rust, generally a deeper shade at the apex. The commonest species of American Rimula, but rare in collections. Dredged 5 to 150 fathoms, especially off the Miami area.

$1/2$ inch in length, conical, laterally compressed, with an elliptical base. 21 to 26 primary radial ribs between each of which are added a smaller, secondary rib farther down. Margin crenulate. Tiny slit just anterior to the apex, and internally it is bordered by a funnel-shaped cup on each side of which is a minute, triangular pit. Color uniformly white, internally glossy. May be collected under rocks at lowest tides in its northern range but also occurs in waters over a mile deep. Common.