600 PLIOCENE MOLLUSCA. 



Distribution. — Recent: Isle of Man, Scotland, Shetland, locally abundant in the 

 Clyde district and the Hebrides ; a smaller variety [australis) has a more southern 

 range (Jeffreys). Norwegian coast. Atlantic coast from Brittany to Gibraltar. 

 Canaries, Mediterranean, Adriatic, ^gean. 



Fossil : St. Erth. Coralline Crag : Sutton, Gedgrave, Corner, 

 Ramsholt. Waltonian : Walton-on-Naze (Kendall). 



Pleistocene : Selsey, Estuarine clays — Belfast, Lochgilphead. 



Miocene : North Germany (Von Koenen), Belgium. 



Lower Pliocene : Piacenziano, Biot. 



Upper Pliocene : Monte Mario, Siena, Altavilla, Val d'Era, Bologna, Livorno, 

 Caltabiano. Scaldisien : Belgium, Holland. 



Pleistocene : Ficarazzi, Monte Pellegrino, Gravina, Livorno, Valle Biaia, Naso. 

 Isocardia- and Tapes-hanks, Christiania. 



Uemarhs. — The present shell was described by Wood at first under the name of 

 0. plicata, but he afterwards identified it with the 0. conoidea of Brocchi — a variable 

 species having a wide range both in time and space. It has been recorded as a 

 fossil from the Miocene deposits of Belgium and Germany, from the Pliocene of 

 Great Britain, Belgium, Holland and the Mediterranean region, as well as from the 

 Pleistocene of a few Sicilian and Italian localities. It occurs also in the later 

 post-glacial T apes-hariks of Christiania, while Prof. Brjafgger includes it among 

 the Lusitanian species of that horizon. 



It is not an abundant form either at St. Erth, in the English Crag or at 

 Selsey. 



As a recent shell it has a wide distribution, though Jeffreys, who took the 

 British variety as characteristic of northern regions, states that the southern form, 

 for which he proposed the varietal name of anstralls, was smaller and narrower. 

 The Crag shells seem to agree most nearly with the former. In the specimens 

 here figured the internal grooving is absent, probably from abrasion. 



Mr. Marshall remarks that 0. conoidea is a very variable species, few of its 

 characters being strongly marked, except the grooved mouth, Mdiich is only visible, 

 however, in about 30 per cent, of a number of specimens, and the tooth, which is 

 always strong and conspicuous. He states also that the convexity of the whorls, 

 the depth of the suture and the keeled periphery are exceedingly variable.^ 



Odostomia polita (Bivona). Plate L, fig. o-t. 



1832. Ovatella ])olita, Bivoua, Eff. scient. Sicil., p. 4, pi. i, fig. 7 ; pi. ii, fig. 7. 



1873 — ^6. Odostomia poUta, Segueuza, Boll. E. Com. Geol. Ital., vol. iv, p. 352, no. 27(3, 1873 ; 



vol. vii, p. 94, no. 564, 1876r 

 1884. Odostomia polita, Monterosato, Nom. Gcu. e Spec. Concli. Medit., p. 93. 



1 Journ. of Couch., vol. ix, p. 230, 1899. 



