NASSA (TBLASCO) COSTULATA. 323 



common in the Waltonian Crag of Little Oakley where I have found hundreds of 

 specimens. It varies in size but retains always the same general character. It 

 seems to have a zonal value. 



Sub-genus TELASCO, H. and A. Adams, 18-53. 

 Nassa (Telasco) costulata (Renieri). 



1804. Buccinum costulatum, Renieri, Tab. Alfab. Couch. Adriat. 



1814. Buccinum costulatum, Brocchi, Conch, foss. subap., vol. ii, p. 343, pi. v, fig-. 9. 



1826. Buccinum Cuvieri, Payraudeau, Moll, de Corse, p. 163, pi. viii, figs. 17, 18. 



1836-44. Buccinum variabile, Philippi, Enum. Moll. Sic, vol. i, p. 221, pi. xii, figs. 1—7, 1836 ; 



vol. ii, p. 188, 1844. 

 1878. Nassa Cuvieri, Monterosato, Enum. e Sinon. Conch, medit., p. 43. 



1882. Nassa costulata, Bucquoy, Dautzenberg et Dollfus, Moll. mar. Rouss., vol. i, p. 52, pi. xi, fig. 15. 

 1901. Nassa (Telasco) costulata, Cossuiann, Ess. Palcoconch. compar., vol. iv, p. 212. 



Var. tenuicosta, Bucquoy, Dautzenberg and Dollfus. Plate XXXIV, figs. 25, 26. 



1882. Nassa costulata, var. tenuicosta, Buccpuoy, Dautzenberg et Dollfus, Moll. mar. Rouss., vol. i, 

 p. 55, pi. xi, fig. 30—32. 



Sjjecific and Varietal Characters. — Shell solid, small, ovato-conical ; whorls 

 but slightly convex ; ornamented by numerous longitudinal costas which extend to 

 the base of the shell, and by very fine spiral ridges ; mouth oval, with a small sinus 

 above ; outer lip thickened by the labial rib, denticulated within ; inner lip forming 

 a distinct glaze on the pillar; canal very short, notched, pinched up at the back. 



Dimensions. — L. 8 mm. B. 4 mm. 



Distribution. — Recent : Mediterranean. 



Fossil: Waltonian Crag: Little Oakley. 



Remarks. — I make no apology for figuring this fragmentary fossil from Oakley, 

 together with a recent shell received from the Marchese di Monterosato with which, 

 so far as it goes, it appears to correspond. It seems different from anything I have 

 noticed before from the Crag, belonging to the group of shells variously known as 

 N. Cuvieri, N. varicosa, etc., which, as before stated, have been associated by the 

 authors of the ' Mollusca of Roussillon ' as varieties of the southern species 

 N. costulata. 1 The Marchese, however, prefers to regard it as specifically distinct. 



The name N. Cuvieri appears in Jeffreys' list of Red Crag shells on the 

 authority of Mr. A. Bell. For reasons given on p. 82 I venture to think that the 

 shell in question, described by the latter as N. variabilis, was a different species, 

 viz. the iV. pusillina of S. V. Wood. 



The sub-genus Telasco is described by Adams as having an elevated spire, 



1 Not the N. costellata of p. 321, which has beeu regarded as belonging to a different group. 



