The undulated brown lines in this shell, are sometimes broken into three irregular bands of either lines or spots, between which are numerous minute dots; in other varieties these dots are only round the suture, and in some totally wanting. Its most constant character rests on the umbilicus, which is rather large, very deep, and without any appearance of the base of the pillar. The mouth is also more contracted than usual. It is said by Adanson to be common on the coast of Senegal; and this observing naturalist adds, that the operculum is testaceous, of a pure white, and marked with numerous concentric grooves at the upper angle.
NATICA punctata,
Spotted Natica.
Generic Character.—See Pl. 75.
Specific Character.
- N. testâ ovato-globosâ, crassâ, albâ, strigis undatis punctisque castaneis ornatâ; umbilico magno, aperto, simplici; columellæ basi obsoletâ.
- Shell ovate-globose, thick, white with waved stripes and minute chesnut dots; umbilicus large, open, simple; base of the pillar obsolete.
- Nerita punctata. Martini 11. pl. 197. f. 1903 and 4. Seba, pl. 38. f. 33? Gualt. pl. 67. f. M. and T. (good.)
- Gochet. Adanson Sen. pl. 13. f. 4.
NATICA effusa.
- N. testâ depressâ, albâ, maculis castaneis ornatâ; spirâ brevissimâ; columellæ basi crassâ, planâ, ad labium interius sinu annexâ.
- Shell depressed, white, with chesnut spots; spire very small; umbilicus large, open, spreading; base of the pillar thick, flat, and united to the inner lip by a sinus.
In form, and sometimes in colour, this shell bears a close resemblance to the oval variety of N. mamilla (Nerita mamilla Lin.); but, the umbilicus, instead of being entirely closed up, is remarkably open, very deep, and the pillar forming an elevated ridge within; colour in the shells of this genus is a very secondary, and, in many cases, a most fallacious guide for the discrimination of the species; for this is sometimes pure white, and I have specimens of N. mamilla entirely orange. This is a rare shell, probably from India.