GASTEROPODA. 87 



anfractibus quatuor vel quinque convexis; suturis profimdis ; longiludinaliter tenuissime 

 costettatis; transversim striatis, decussatis ; labro acuto ; umbilico mediocri ; columettd 

 obsolete unidentd. 



Shell small, thin, fragile, and pellucid (?) with four or five convex volutions, and 

 a deep and distinct suture ; longitudinally costulated with 18 22 slightly raised ribs 

 decussated by seven or eight transverse lines ; aperture ovate ; outer lip sharp and 

 plain within ; a small but distinct umbilicus; and a rather obscure fold upon the 

 columella. 



Axis, \ of an inch. 



Locality. Cor. Crag. Sutton. Recent, British Seas. 



I have procured about half a dozen specimens of this elegant little shell, some 

 of which are in sufficiently good preservation to be identified. The opportunity of 

 comparison with a recent specimen has been obligingly afforded me by Mr. Thompson 

 of Belfast, and I have every reason to think they are the same. The apex is obtuse, 

 but not reversed. There is a small but obscure fold upon the columella, scarcely 

 discernible, except where the outer lip is broken away. 



4. ODOSTOMIA SIMILLIMA (?). Mont. Tab. IX, fig. 6, a b. 



TURBO SIMILLIMUS. Mont. Test. Brit. Sup. p. 136, 1803. 



7Fern.Mem. vol. i, p. 406, t. 8, fig. 15. 



Turt. Conch. Diet. p. 209, 1819. 



TUKBITELLA SIMILLIMA. Flem. Brit. An. p. 303, 1828. 

 RISSOA (?) COSTELLATA. S. Wood. Catalogue 1842. 



Od. Testa pusilld, elongatd, subulatd, gracili ; apice obtuso ; anfractibus quinque 

 convexis ; suturis pro/undis ; longitudinaliter costellatis ; costellis rectis ; aperturd ovatd, 

 simplici, dimidiam spiram cequante ; sine umbilico. 



Shell minute, elongate, tapering, and slender, with an obtuse and reversed apex ; 

 volutions five, convex ; suture deep, longitudinally costellated, with perfectly straight 

 ribs ; aperture ovate, rather elongate ; last volution large, measuring half the axis. 



Axis, \ of an inch. 



Locality. Cor. Crag, Sutton. Recent, British Seas. 



I have but a few specimens of this elegant little shell, which appear to differ in 

 some characters from the description of its recent analogue, to which I have referred 

 it with doubt. It is much smaller, and the costae are broad and smooth, having twenty 

 in the last volution. The spaces between them are very narrow ; the suture is sub- 

 canaliculated, by the upper part of the outer lip being somewhat slightly raised, 

 and there is a small obscure tooth upon the columella ; my specimens are not in very 

 good condition. Turton gives the recent shell as found on the shores of the island of 

 Jura. 



