Volume Ii Part 5 (1/2)

NATICA melastoma,

_Black-mouthed Natica--lower figures._

_N. testa depressa, fusca; spira complanata minima; ore intus atro-purpureo; umbilico magno, clauso labio interiore rufo._

Sh.e.l.l depressed, brown; spire flattened, very small; mouth within purplish black; umbilicus large, closed up by the inner lip, which is rufous.

In colour this bears a close resemblance to the last, but the sh.e.l.l is flattened beneath, and the spire very short and depressed; the umbilicus large, but, in general, quite closed up by the thickness of the pillar, united to the inner lip. In some specimens a narrow crescent-shaped groove is left on the outside margin. Its habitat is unknown.

Pl. 80

[Ill.u.s.tration]

HALIOTIS Californiensis,

_Small-holed Californian Ear-sh.e.l.l._

GENERIC CHARACTER.

_Testa univalvis, depressissima, lata, auriformis. Discus admodum perforatus. Spira minuta, depressa. Apertura testam magnitudine pene aequans, intus margaritifera._

Typus Genericus _H. Tuberculata_ Linn. &c.

Sh.e.l.l univalve, greatly depressed, broad, ear-shaped, the disk with many perforations. Spire minute, depressed. Aperture nearly as large as the sh.e.l.l; inside pearly.

Generic Type _H. Tuberculata_ Linn. &c.

SPECIFIC CHARACTER.

_H. Testa ovali, laevi, obscure thala.s.sina; labio exteriore supra immarginato, interiore lato, complanato, foraminibus numerosis, minutis, orbicularibus, laevibus._

Sh.e.l.l ovate, smooth, obscure sea green; outer lip above immarginate; inner lip broad, flat; perforations numerous, very small, orbicular and smooth.

The Ear-sh.e.l.ls are strangely characterized by their peculiarity of form, perforated holes, and rich pearly interior. They are found in both temperate and tropical seas; but the definitions. .h.i.therto given by conchologists are so imperfect, that they have left our knowledge of these sh.e.l.ls nearly the same now, as in the time of Linnaeus. Seventeen species only are enumerated in Mr. Dillwyn's work; although thirty-four have fallen within my own observation the last few months.

The difference between this and the common black Californian Ear, consists in its being a much deeper and smoother sh.e.l.l, always narrowest at the base, the outer lip not having (as in that) a prominent curve or gibbosity where it joins the spire; but princ.i.p.ally in the perforations, which in this are always half as large, and doubly numerous; it is also generally a much smaller, and less common species: the spire is always deeply tinged with pink. The genus _Padollus_, of Montford, resting entirely in the unevenness of the outer lip, without any knowledge of the animal, appears to me an unnecessary distinction, for such is the character of all young sh.e.l.ls, and also of mature ones, whose outer surface is rugged or uneven.

Pl. 81