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.
F. Græca.
F. nodosa.
F. Cayennensis.
F. lilacina.
F. rosea.
F. Barbadensis.
F. radiata.
F. viridula.
F. hiantula.
F. pustula.
F. fascicularis.
F. Javanicensis.
F. depressa.
F. Peruviana.
F. gibberula.
F. minuta.
_F. nimbosa._ The scaly-ribbed Fissurella.
Species of which the middle part of the edges of the aperture is
hollowed in such a manner that, when placed on a level surface, they
touch only at the extremities.
_F. rosea._ The rosy Fissurella.
Species more depressed, edges bent up lengthwise, forming a kind of
canal.
_F. Græca._ The Greek Fissurella. Pl. 32, fig. 1.
Conical, ovate oblong; striæ cancellated and elevated; sections
tuberculated; exterior yellowish brown or clouded, interior white or
light blue.