rERTTHIOPSIS TUBERCULARIS. 527 



Geiia.s CERITHIOPSIS, Forbes and Haiiley {continued from Vol. I, p. 424.). 

 Cerithiopsis tubercularis, var. subulata (S. V. Wood). Plate XLVII, fig. G. 



1848. Cerithium tnhercidare, var. subidatiim, S. V. Wood, Mou. Crag Moll., pt. i, p. 70, pi. viii, 



fig. 5 b. 

 1865. Cerithiopsis acicula, Brusiua, Conch. Dalin. ined., p. 17. 

 1884. Cerithiopsis tuhercidaris, var. subulata, Bucquoy, Dautzeuberg- et Dollfus, Moll, mar, Roiiss., 



vol. i, p. 205, pi. xxvii, tig. 3. 

 1898. Cerithiopsis minutum, A. Bell, Trans. Koj. Geol. Soc. Cornwall, vol. xii, p. 144. 



Varietal Characters. — Differs from the type in its slender, elongated and sub- 

 cylindrical spire and in its flattened whorls. 



Dimensions. — L. 5 mm. B. 1 mm. 



Dlstrihidlon. — Recent : Guernsey, Bantry Bay and elsewhere. Mediterranean, 

 Adriatic. 



Fossil : St. Erth. Coralline Crag: Sutton. 



Uemarhs. — This well-marked variety was first described by Wood from the 

 Coralline Crag. The specimen now figured is from the Warburton Collection of St. 

 Erth fossils in the British Museum, where it is labelled Gerlthiani minimum. The 

 species reported by me, however, under that name in Vol. I of the present work, 

 p. 423, PI. XLI, figs. 22, 23, is a shorter and wider shell and is the variety nana 

 of Wood. 



Qenus SCALA, Klein, 1753. 



The use of the generic term Scalarla (Lamarck, 1801), by which the group of 

 moUusca described below was so long known, has been recently discontinued in 

 favour of the earlier and pre-Linnean one given above. The Scalidge, moreover, 

 have been of late much subdivided, and the names of many new sub-genera are 

 now found in recent conchological works. 



The nomenclature here used is in the main that adopted by M. Cossmann in the 

 ninth volume of his " Essais de Paleoconchologie comparee " (1912), in collabora- 

 tion with M. de Boury of Paris, who has devoted many years to the study of the 

 Scalas, upon which he is regarded as a distinguished authority. As no less than 

 sixteen of these subdivisions are represented in the English Crag, and there are 

 some other points which deserve discussion, it seems desirable in the present 

 memoir to deal with the Crag Scalas as a whole. 



It is not practicable, however, that the characteristic features of these different 

 groups can be fully given here ; a reference, therefore, to M. Cossmann's work is 

 recommended to those who desire a more detailed knowledge of the subject. 



