E. fissura. The slit Emarginula. Pl. [32], fig. 5.
Oval, compressed, summit well marked, with reticulated striæ and ribs; fissure extending half way from the margin to the summit; exterior light brown, interior white.
E. marginata. The marginated Emarginula.
More compressed than the preceding; summit distinct, anterior margin formed like a gutter.
3. Fissurella. The Keyhole Limpet. Nineteen species.
The perforation not being perfectly round, but generally ovate oblong, procured for this genus its common name, by which it is easily distinguished.
Shell simple, conical, depressed, recurved; summit perforated a little anterior in an oblong or oval manner, like a keyhole; the exterior surface ribbed longitudinally, slightly striated transversely.
Fissurella picta.
F. nimbosa.
F. crassa.