Shell univalve, greatly depressed, broad, ear-shaped, the disk with many perforations. Spire minute, depressed. Aperture nearly as large as the shell; inside pearly. Generic Type _H. Tuberculata_ Linn. &c. * * * * * SPECIFIC CHARACTER. _H. Testa ovali, laevi, obscure thalassina; labio exteriore supra immarginato, interiore lato, complanato, foraminibus numerosis, minutis, orbicularibus, laevibus._ Shell ovate, smooth, obscure sea green; outer lip above immarginate; inner lip broad, flat; perforations numerous, very small, orbicular and smooth. * * * * * The Ear-shells 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 hitherto given by conchologists are so imperfect, that they have left our knowledge of these shells 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 shell, always narrowest at the base, the outer lip not having (as in that) a prominent curve or gibbosity where it joins the spire; but principally 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 shells, and also of mature ones, whose outer surface is rugged or uneven. * * * * * Pl. 81 [Illustration] SPHINX Ello. * * * * * GENERIC CHARACTER. _Antennae prismaticae, in utroque sexu ad medium leviter crassescentes, externe breviter piloso baciliatae, mucrone arcuato, producto, sensim terminantes. Palpi breves, obtusi. Lingua elongata, convoluta, distincta, et in pupa aliquando porrecta. Alae sub-integrae. Abdomen elongatum, conicum, ano acuto, imberbi._ Typus Genericus _Sphinx Convolvuli_ Linn. Antennae three sided, in both sexes slightly thickened in the middle, externally ciliated with double tufts of short hairs, and ending in a gradually lengthened arcuated hook. Palpi short, obtuse. Tongue long, convolute, distinct, sometimes porrected in the pupa state. Wings nearly entire. Abdomen lengthened, conic; the tip pointed, and not bearded. Generic Type _Sphinx Convolvuli_ Linn. * * * * * SPECIFIC CHARACTER.