Volume Ii Part 3 (1/2)

Typus Genericus _Nerita Glaucina_ Pennant.

Sh.e.l.l nearly globose, or oval, umbilicated. Spire depressed, very small. Columella terminating in the middle of the umbilicus. Aperture semi-circular, operculum either h.o.r.n.y or testaceous. Animal marine, with a large foot; the eyes placed at the base of two simple tentacula.

Generic Type _Nerita Glaucina_ Pennant, &c.

SPECIFIC CHARACTER.

_N. testa sub-globosa, fusca, albo fulvoque fasciata, juxta suturam striata; labio exteriore supra leviter emarginato; umbilico magno, aperto; columella obsolete terminante._

Sh.e.l.l sub-globose, striated near the suture, brown, banded with white and fulvous; outer lip above slightly emarginate; umbilicus large, open; pillar termination nearly obsolete.

_Martini_ 5. _pl._ 187. _fig._ 1872 _&_ 3. _fig._ 1874 & 5? _pl._ 188.

_fig._ 1896, 8 _&_ 9.

_Seba_, _pl._ 38. _fig._ 66. _pl._ 41. _fig._ 14, 15.

The Sh.e.l.ls of this genus are composed of such of the Linnaean _Nerits_ as are umbilicated, from which latter they essentially differ, both in the organization of the animal and the construction of the sh.e.l.l, which is either closed by a sh.e.l.ly or h.o.r.n.y operculum.

The species are numerous, and are found both in temperate and tropical seas; two or three inhabit our own coasts, but by far the greater number are found in the Asiatic Ocean. They are subject to variation in their colour; and this, joined with a general resemblance in form, has rendered the discrimination of the species very difficult. I have, however, remarked, that the various modifications of the umbilicus, and the termination of the pillar (which is indicated in many species by an elevated ridge or rib within the umbilicus) is a certain and constant indication, presenting the same peculiarity through all the individuals of a species, even in the young state. This termination of the pillar has been mistaken for the inner lip, which, on the contrary, is always above the umbilicus, which, if closed, is not closed by the lip, but by the thickened termination of the pillar or columella.

The two most striking varieties are here figured of this species, which is sufficiently described in the specific character. I believe it is found both in the Mediterranean and Red Seas.

Pl. 76

[Ill.u.s.tration]

MEROPS Savignii,

_Black-capped Bee-eater._

GENERIC CHARACTER.--See Pl. 8.

SPECIFIC CHARACTER.

_M. viridis, subtus albescens, uropygio caudaque caeruleis; vertice, striga oculari, fasciaque lata collari nigris; mento, superciliisque albis; rectricibus mediis elongatis._

Green; beneath whitish; rump and tail blue; crown of the head, eye stripe, and broad band across the neck, black; chin and eye-brows white; two middle tail feathers lengthened.