N. elliptica. The oval Navicella.
Shell covered with olive epidermis, under which it is smooth, shining, spotted and streaked with purple, blue, or brown; spire curved, prominent, extending beyond the margin.
3. Nerita. The Hoof Shell. Seventeen species.
A marine shell, never spined, but variously striated. Some species of this genus are very beautiful; they are frequently worn as ornaments by the Indians.
Shell solid, thick, more or less globular, flat beneath, spire but little, if at all, projecting, not umbilicated; aperture large, semilunar, very entire; the external margin very much hollowed; the internal or columellar straight, sharp, and shaped like a partition, often dentated; operculum horny or calcareous, sub-spiral; the summit entirely marginal at its extremity, implanted by teeth more or less marked, and sunk in the columellar margin, on which it seems articulated.
Nerita exuvia.
N. textilis.
N. undata.
N. peloronta.
N. chlorostoma.