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Published online by Cambridge University Press: 17 March 2016
In the Plate accompanying this paper are figured three species of Terebratulæ, which the writer lately obtained from the Lower Greensand beds of the Isle of Wight. Two of them are interesting as being entirely new to these strata in Britain, whilst the third is a remarkable deformity of a rare species. In Fig. 1, 2, 4, a shell is drawn which appears to be identical with the Terebratula Moutoniana of D'Orbigny, a species not uncommon in France, associated with T. sella in the Upper Neocomian and Aptian beds of that author. It is somewhat oval in shape, depressed and elongated; surface entirely smooth. The perforate valve is rather more convex than the other, truncated by a foramen of moderate size; deltidium very short and small. Nine specimens of this species were obtained from the ferruginous Greensand beds, at Dunnose Point, near Shanklin. This shell, on external examination, is easily distinguished from T. sella, which it somewhat resembles, by the absence of any biplication on the frontal margin. Its internal structure proves it to belong to the section Waldheimia of King, which precludes all doubt as to its specific distinctions from T. sella. It is easily distinguished from Waldheimia Celtica, Morris, by its less elongated and gibbous outline.
page 415 note * The shell to which M. D'Orbigny has erroneously applied Sowerby's name of T. faba, is identical with the T. Celtica of Morris. The T. faba of Sowerby is merely a variety of T. biplicata confined to Upper Greensand strata.
page 415 note † T. Carteroniana and T. Collinaria appear to have heen regarded in this country as forms of T. sella.