220 EOCENE MOLLUSCA. 



pointed, formed of nine or ten volutions : whorls angulated at the shoulders, and armed 

 with a single row of large, pointed, rather distant tubercles ; the posterior margins 

 wide, concave, thickened and obliquely plicated at the suture, and ornamented with 

 several fine concentric raised lines ; of these, two running round the border are more 

 elevated than the rest, and are decussated and feebly granulated by the plication on the 

 edge, and two others, running along the hollow part of the margin, are also rather pro- 

 minent and granulated by the lines of growth. The last whorl is somewhat turbinate, 

 and terminates in front in a long, moderately wide, straight canal. The bands on the 

 middle and front surfaces of the whorls are numerous, coarse, irregular, and very 

 unequal, and much roughened by the lines of growth ; three or four over the middle 

 part of the whorls are thicker and more prominent than the rest, and between them 

 appear two or three smaller unequal bands. The aperture is of an oblong, ovate form ; 

 the outer lip much arched ; the sinus deep, moderately wide, sub-trigonal, and placed 

 in the very middle of the margin. 



This beautiful and well-marked species was first obtained from the Artesian well 

 at Southampton, by Mr. Keele, to whom I have ventured to dedicate it. 



Size. — Axis, 3 inches and 3-12ths; diameter, 1 inch and l-12th. 



Localities. — Southampton and Shenfield. 



No. 146. Pleurotoma dentata, Lamarck. Tab. XXVI, fig. 5. 



Pleurotoma dentata, Lamk. 1804. Ann. du Mus., vol. iii, p. 167, No. 8 ; vol. vii, t. 13, 



fig. 1. 

 _ _ lb. 1822. Hist, nat., vol. vii, p. 99, No. 13. 



_ _ Be Til. 1826. Diet, des sci. nat., vol. xli, p. 395. 



— costulifera? Bronn* 1827. Zeitschrift fiir Mineral., band ii, p. 535, No. 120. 



— dentata, lb. 183 1. Italiens tertiargeb., p. 46, No. 222. 



— — Desh. 1832. Enc. meth. (Vers), vol. iii, p. 797, t. 440, fig. 8, 



No. 16. 



— lb. 1824-37- Descr. des coq. foss., &c, vol. ii, p. 452, t. 62, 



figs. 3, 4, 7, 8. 



— — Morris. 1843. Cat. Brit. Foss., p. 157. 



— Sow. 1850. Dixon's Geol., &c, of Sussex, p. 102, t. 6, fig. 24. 



— — Rouault. 1848. Desc. des foss., &c., de Pau (Mem. de la Soc. Geol. 



de France, 2d series, vol. iii, p. 484), No. 92, t. 16, fig. 24. 

 VOrb. 1853. Prod, de Paleont., vol. ii, p. 358, No. 3S2. 



— — Morris. 1854. Cat. Brit. Foss., 2d edit., p. 270. 



P. testa elongatd, fusi/ormi, undique concentrice lineatd ; spird elevatd, acuminata: 

 anfractibus convexiusculis, angulatis, dentato-tuberculatis ; marginibus posticis mediocriter 

 /atis, vix cavatis, ad suturas pauxillum incrassatis ; ultimo anfractu in canali longo termi- 



