Hab. Monterey, 20 fms. Dr. Cooper. Also fossil, not rare, in the Post Pliocene of San Pedro and Santa Barbara, where some specimens have been found an inch in height.
No. 355, Mollusca, Survey Collection.
This shell appears to be allied to the genera Calliostoma and Thalotia, from which it is separated by the peculiar mouth. In the absence of the operculum, it is impossible to define its position certainly.
EMARGINULA, Lam.
E. bella, G.
E. t. alba, oblongo-ovalis, subelevata, antice parum convexa, postice excavata, parte anteriori angustiori; apice excentrico, prominente, parum recurvato; sinu mediocri; costis radiantibus circiter XIX cum costis minoribus interstitialibus irregularitur alternantibus, per lineas concentricas clathratis.
Long. ·55, lat. ·36, alt. ·22.
Shell oblong oval, somewhat elevated, narrowest anteriorly; apex excentric, posterior, prominent and somewhat recurved; outline in front of the apex slightly convex, from the apex to the posterior margin slightly excavated, sides descending nearly straight; sinus moderate, variable, situated at the extremity of a strong rib; surface ornamented by about nineteen large radiating ribs, with smaller ones interposed, all crossed by moderately prominent concentric ridges; color white.
Locality Monterey, Dr. Cooper. “Two dredged dead.”