RISSOA VENUSTA. 627 



1884. Zippora elata, Monterosato, Nom. Gen. e Spec. Conch. Medit., p. 54. 



1890. Bissoa (Zippora) elata, Cams, Prod. Faun. Medit., vol. ii, p. 323. 



1892 — 98. Rissoia membra nacea, var. elata, A. Bell, Eep. Yorks. Phil. See, p. 63, 1892 ; Proc. Roy. 



Irish Acad. [3], vol. ii, p. 630, 1893 ; Trans. Eoy. Geol. Soc. Cornwall, vol. .\ii, p. 153, 1898. 

 1892. Rissoia elata, Locard, Coq. mar. Cotes de France, p. 1()7. 



1898. Rissoa elata, Bncquoj, Dautzeuberg et Dollfus, Moll. mar. Roiiss., vol. ii, p. 799. 

 1901. Zippora mettiljranacea, var. elata. Conch. Soc. List, Journ. of Conch., vol. x, p. 18. 



Svecific Characters. — Shell elongato-tiirreted, with an acute apex ; whorls 

 about 10, the upper ones flattened, the lower ones somewhat more convex ; spire 

 regularly conical ; suture slight, rather oblique, marked by numerous but not 

 prominent ribs or lines of growth and l)y more or less obsolete spiral lines; mouth 

 oval, rounded and expanded l^elow ; inner lip expanded, forming a small umbilical 

 chink. 



Dimensions. — L. 10 mm. B. 4- mm. 



Distribution. — -Recent : British Seas, estuaries and brackish water (Jeffreys). 

 Mediterranean, Adriatic, Black Sea. Atlantic coasts of Spain. 

 Fossil : St. Erth. Selsey. Belfast clays. 



Pliocene : Livorno, Altavilla. 



Pleistocene : Livorno, Monte Pellegrino. 



Remarks. — -This form was originally considered by Philippi and since then by 

 other writers as specifically distinct. By Jeffreys, and more recently by the 

 Conchological Society, however, it has been regarded as a variety of R. memhranacea. 

 Jeffreys describes it as thinner than the latter, with a longer spire and often 

 ribless. In Philippi's figure it is shown to l)e slender, elongated, with incon- 

 spicuous and nearly straight ribs, approaching one of the Belfast fossils alluded to 

 above, but having a longer spire. Two of the specimens of R. lahiosa figured by 

 Forbes and Hanley (pi. Ixxvii, fig. 3 ; pi. Ixxxi, fig. 3) seem to belong to this 

 form. There are recent examples in the Holmes Collection at the IN^orwich 

 Museum which corres])ond exactly with it. Mr. A. Bell reports it from St. Erth 

 and Selsey, and Seguenza from the Upper Pliocene and Pleistocene of Livorno and 

 Sicily. 



Eissoa venusta, Philippi. Plate LI, fig. 14. 



1844. Rissoa venvsta, Philippi, Enum. Moll. Sic, vol. ii, p. 124, pi. xxiii, fig. 4. 



1867. Rissoa memhranacea var. venasta, Jeffreys, Brit. Conch., vol. iv, p. 31. 



1890. Rissoa venusta, Carus, Prod. Faun. Medit., vol. ii, p. 323. 



1892. Rissoa venusta, Locard, Coq. mar. Cotes de France, p. 170. 



1892. Rissoa memhranacea var. venusta, A. Bell, Kep. Yorks. Phil. Soc, p. 63. 



1892. Rissoa memhranacea var. venusta, Praeger, Proc. Roy. Irish Acad. [3], vol. ii, pp. 260, 277. 



1898. Rissoa venusta, Bucquoy, Dautzenberg et Dollfus, Moll. mar. Ronss., vol. ii, p. 796. 



Specific CJiaracfers. — Shell solid, ovate; whorls but slightly convex, the last 

 two-thirds the total length ; ornamented by strong longitudinal costa3, which die 



