58 PLIOCENE MOLLUSCA. 



Bemarlcs. — Wood figured a specimen of this species from Bridlington, but up 

 to the present it has not been noticed from the Crag. I have a unique example 

 from Oakley, and it may probably be found elsewhere if specially looked for. My 

 Crag shell is worn and does not show either the spiral lines at the base of the shell, 

 or the fine inconspicuous ribs on the upper whorls.^ It corresponds sufficiently, 

 however, with some fossils which Mr. A. Bell obtained from a Pleistocene deposit 

 at Lochaber, N.B., to be identified with them. 



This species was known to Moller, Wood and others as C. HolholUi, but Gould's 

 name rosacea is slightly older. It is a northern form which is not known, either 

 from the Christiania fiord or the southern coasts of Norway. Messrs Dautzenberg 

 and Fischer state that it has been dredged in Norwegian seas, and in those of New 

 England at depths varying from 5 to 548 metres. Although grouping it with the 

 Columbellas they state that the conformation of the operculum is not unlike that 

 of Purpura. 



Genus CASSIDARIA, Lamarck, 1812. 

 Cassidaria tyrrhena (Chemnitz). Plate II, fig. 13. 



1788. Buccinum cassideum thyrheruim, Cliemuitz, Conch. Cab., vol. x, p. 192, tab. 153, figs. 1461, 



1462. 

 1836-44. Cassidaria tyrrhena (part), Pliilippi, En. Moll. Sic, vol. i,p. 216, 1836 ; vol. ii, p. 1S6, 1844. 

 1859. Cassidaria tyrrhena, Cheuu, Man. Conch., vol. i, p. 208, fig. 1136. 

 1873-75. Cassidaria tyrrhena, Seguenza, Boll. K. Com. Geol., vol. iv, p. 300, 1873; vol. v, p. 276, 



1874; vol. vi, p. 278, 1875. 



1881. Cassidaria bicatenata, var., Nyst, Conch. Terr. Tert. Belg., pi. ii, fig. 14 6, 14 c. 



1882. Cassidaria tyrrhena (rugosa), Bucquoy, ^Dautzenberg, et Dollfus, Moll. mar. Rouss., vol. i, 

 p. 70, pi. ix, fig. 3. 



1890. Cassidaria tyrrhena, Carus, Prod. Faun. Med., vol. ii, p. 375. 



1901. Cassidaria tyrrhena, Kobelt, Icon, schalentrag. europ. Meeresconcli., vol. ii, p. 71, pi. xlviii, 

 figs. 1 — 5. 



Specific Characters. — Shell ovate, subpyriform, ventricose ; whorls convex, the 

 last much the largest; ornamented with numerous fine and regular ridges, and some- 

 times with a row of tubercles, not very prominent, on the upper part of the lower 

 whorl ; mouth oval, ending in a short canal which turns to the left ; columella 

 excavated; suture distinct. 



Dimensions. — (Of Crag specimen) L. 45 mm. B. 30 mm. 



Distribution. — Recent: Mediterranean; Adriatic; west European. 



Fossil : Coralline Crag : Boyton. Waltonian : Little Oakley. 

 Pliocene : Italy, North Germany, Algeria. Upper Pliocene and Pleistocene 

 deposits : Sicily. 



^ MM. Dautzenberg and Fischer state that such features are not always present in this species. 



