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EOCENE MOLLUSCA. 



No. 202. Pleurotoma divisa. F. E. Edwards. Tab. XXXI, fig. 17, a, b. 



P. testa fusiformi, longitudinaliter costcllatd, spiraliter obscure lineatd : spird obtusd, 

 corded : anfraclibus convexis, postice sulco concentrico exilissime lineato exaratis ; costellis 

 crassis, rotundatis, obliquis, curvis, ad suturam tendentibus, sulco marginali divisis ; lineis 

 spiralibus confertis, obsoletis : aperlurd ovali, antice in canali longiusculo exeunii ; labro 

 valde arcuato, ad humerum sinuato ; sinu lalo, paulo prof undo, sub-lrigono. 



A wide, fusiform shell, longitudinally ribbed and concentrically lined ; the spire 

 thick, conical, and elevated, forming nearly one half of the entire length of the shell ; the 

 whorls, seven or eight, exclusive of the pullus, convex ; the posterior margins narrow, 

 hollowed out by a moderately wide and shallow spiral furrow, the concentric lines 

 over which are more prominent and distinct than those over the other parts of the 

 whorl ; the last whorl contracts somewhat suddenly towards the front and terminates 

 in a widish, moderately straight canal. The ribs are numerous, thick, rounded 

 on the upper surface, arched and long, stretching backwards to the sutural margin, 

 and extending in front to the canal; immediately behind the shoulder they are 

 crossed by the marginal furrow, by which they are divided in two, giving to the spire 

 the appearance of being girt by a double row of tubercles. The spiral lines on the 

 early whorls are sharp and distinct ; but on the later whorls, except over the marginal 

 furrow, they are so feeble and obscure as scarcely to interfere with the smoothness of 

 the surface. The aperture is oval ; the outer lip much and regularly arched ; and the 

 sinus, which is placed on the shoulder, wide, shallow, and triangular in form. 



The present species appears to be perfectly distinct ; it is very rare. 



Size.— Axis, 10-1 2ths of an inch ; diameter, 4-12ths of an inch. 



Locality. — Bracklesham Bay. 



No. 203. Pleurotoma Selysii. Be Koninck. Tab. XXIX, fig. 17, a — d. 



Pleurotoma Selysii. De Kon. 1837. Coq. foss. de Basele, &c, p. 25, t. I, fig. 4. 



— rostrata. — — Ibid., p. 24, No. 23 (non Sol.) (excl. syn.) 



— acuminata. — — Ibid., p. 24, No. 24 (non Sow.) 



— Selysii. Nyst. 1843. Coq. et Polyp, foss. de Belg., p. 515, t. 40, figs. II a. 



lib, and 12. 



— — Nyst. 1843. Bull. Soc. Geol. de France, vol. xiv, p. 453. 



P. testa fusiformi, turritd, undique concentrice lineatd ; spird acuminata : anfractibu,s 

 convexiusculis, postice excavatis, crenulatis, ad humeros tuberculato-plicatis ; ultimo anfractu 

 in canalem longiusculum producto ; lineis concentricis supra margines el humeros confertis, 

 exilibus, regularibus ; cceteris crassioribus, distantioribus, irrcgularibus ; plicis flexuosis .- 

 aperlurd oblongo-ovali ; sinu latissimo, triangulari, ad humerum collocato. 



