. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. nKMiTROcnus. 175 The j:\w is stronf^ly arched with acuminatod ends, smooth ant«!rior surface, and decided median prominence to cutting mar<;in. Fig. 84 represents the jaw of variiina. The other AVest-Indian s|ie(; examined ]jy me ' •' Fiff. 84. have the same type of jaw. The lingual memhrane (IM. IV. Fig. L) has about 33—1—33 teeth; another specimen gave 43—1—43 teeth, Avith 17 perfect laterals. The central tooth lias a long, narrow base of attach- Jaw of , . , . , , //• varians. nient with lower, oute
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. nKMiTROcnus. 175 The j:\w is stronf^ly arched with acuminatod ends, smooth ant«!rior surface, and decided median prominence to cutting mar<;in. Fig. 84 represents the jaw of variiina. The other AVest-Indian s|ie(; examined ]jy me ' •' Fiff. 84. have the same type of jaw. The lingual memhrane (IM. IV. Fig. L) has about 33—1—33 teeth; another specimen gave 43—1—43 teeth, Avith 17 perfect laterals. The central tooth lias a long, narrow base of attach- Jaw of , . , . , , //• varians. nient with lower, outer angular expansions and incurved lower margin. The reflected portion is only about one half the length of the base of attachment, is short, and bears one short, stout cusp with an e(iually short, stout cutting point; the side cusps and cutting points are obsolete. The lat- erals are the same as the centrals, but asymmetrical. The outer laterals, com- mencing at the 11th, have a side cusp and cutting point; the inner cutting point is bifid on the 16th tooth; after this the change into the marginals is rapid. The marginals are low, wide, and have one broad, long, oblique, bluntly bifid cutting point, the inner division the smaller, and a very much shorter side cutting point. This side cutting point is also sometimes bluntly bifid in the extreme marginal teeth. The dentition of the other species of this genus, extralimital to North America, examined by me, agrees with that of this species. (See Pr. Phila. Ac. Nat. Sc. 1874, 56.) Hemitrochus varians, Menke. Vol. III. Pis. XLVI., XLVII. Shell subimperforate, of medium size, solid, conic-globose, delicately striate, but leaving the surface smooth and shining ; the ground-color is variable, being white, dusky, greenish or reddish, and either plain or variously encircled by dark bands; the apex and the peristome, especially the columellar portion, is always rose-red, and generally, likewise, the throat; the spire is eleva
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Keywords: ., bookauthorha, bookcentury1800, bookdecade1860, booksubjectzoology
