232 PLIOCENE MOLLUSCA. 



1867. Defrancia purpurea, Jeffreys, Brit. Couch., vol. iv, p. 373, pi. Lxxxix, fig. 5. 



1870. Defrancia purpurea, A. Bell, Jouru. de Conch., vol. xviii, p. 348, no. 294. 



1872. Defrancia purpurea, A. and E. Bell, Proc. Geol. Assoc, vol. ii, p. 213. 



1873-5. Defrancia purpurea, ^eg\\&nzdi,,'Bo\\. R. Com. Geol. Italia, vol. iv, p. 298, no. 127, 1873; vol. 



Ti,p. 208, no. 190, 1875. 

 1877. Homotoma purpnrei, Bellardi, Moll. Terr. Terz. Piem., pt. ii, p. 270. 

 1883. ClathureJla purpurea, Bucquoy, Dautzenberg et DoUfus, Moll. mar. Rouss., vol. i, p. 90, pi. xiv, 



figs. 6, 7. 



1889. Defrancia purpurea, A. Bell, Proc. Roy. Phys. Soc. Edin., vol. x, p. 296. 



1890. Clathurella pxirpurea, Cams, Prod. Faun. Medit., vol. ii, p. 425. 



1901. ClathureUa purpurea, Br^gger, Noi'ges geol. unders0gelse, vol. xxxi, p. 661. 



1905. ClathureUa (Philbertia) purpurea, Kobelt, Icon, schaleutrag. europ. Meerescouch., vol. iii, 



p. 359, pi. xcv, figs. 21—23. 

 1910. Peratoto ma purpurea, Cerulli-Irelli, Palaeout. Ital., vol. xvi, p. 5S, pi. v, figs. 34, 35. 



Specific CJiaracters. — Shell subturriculate, elongated, rather solid; whorls con- 

 vex and rounded ; ornamented by numerons longitudinal ribs, not very prominent, 

 closely crowded together, and by well-marked, regular, wavy and equidistant 

 transverse ridges, becoming slightly granular where they cross the ribs, and giving 

 the shell a clathrate appearance ; suture fairly deep ; apex acute ; mouth ovate, 

 contracted and angulate alcove ; labial sinus clearly marked ; outer lip thickened 

 and strongly denticulate within ; canal distinct, short, open. 



Dimensions. — L. 12 — 22 mm. B. 4 — 8 mm. 



Blstrihution. — Iiecent : Mediterranean, Adriatic, yEgean, Atlantic from the 

 Canaries northwards to Great Britain (southern and western coasts), Skye and 

 Shetland, Christiansand, Bergen, Bohuslan. 



Fossil : Coralline Crag : Sutton, Boy ton. Waltonian : Walton- 

 on-Naze (A. Bell), Little Oakley. Butleyan : Butley. Holocene : Portrush. 



Upper Pliocene : Italy — Piedmont, Monte Mario ; France — Biot ; Sicily — 

 Altavilla. 



Pleistocene : Italy — Livorno, Taranto, Valle Biaia ; Sicily — Monte Pellegrino, 

 Ficarazzi, Catania. 



Tapes and Isocardia banks : Christiania (Br^gger), Trondhjem (0yen). 



IlemarJcs. — The generic name ClathureUa was substituted for Defrancia (Millet, 

 1826), the latter having been proposed the year before for a group of Polyzoa. It 

 has been used for some small shells allied to Mangilla, having a clathrate sculpture, 

 and has been divided lately into several sub-genera. Italian conchologists have 

 adopted the generic name of Peratofoma , with several sub-divisions, for the present 

 group and some other shells. 



Although C. purpurea and some other nearly allied Crag Clathurellas are now 

 found living in a few places as far north as the southern coasts of Sweden and 

 Norway, they form, taken as a whole, a southern group of Mollusca, widely 

 diffused in the Mediterranean and occurring on the southern and western shores of 



