250 
GASTEROPODA OF THE INFERIOR OOLITE. 
mvUistriata. These distinctions differentiate the North Dorset fossils more from 
the typical forms than any characters ascribed by Oppel to his Ph. Ssemanni. 
The most typical forms, and those most easily matched by Corallian specimens 
occur in the well known beds on Cleeve Hill. Yorkshire specimens from White 
Nab, to judge by the figure of Morris and Lycett, are similar to these, but perhaps 
with fewer strim. In all the localities (both Inferior Oolite and Corallian) there 
seems to be a broad and narrow variety side by side. 
Relations and Distribution . — This variable species almost constitutes a genus 
in itself, but the varieties for the most part repeat themselves on the several 
horizons. 
The var. multistriata occurs sparingly in the Murcliisonse-zonQ of Bradford 
Abbas. The more ordinary forms occur in the Pea-grit of the Cotteswolds. The 
beds on Cleeve Hill, though higher, still belong to the Lower Division, and not to 
the Humpliriesianus -zor\G. The Scarborough Limestone of White Nab, however, 
contains the Ammonites of this zone. Small specimens of Bourguetia striata^ 
much defaced, occur in the Lincolnshire Limestone at Weldon. 
“ Pliasianella ” costata, Witchell (‘ Proc. Cottes. Nat. Eld. Club,’ 1879 — 80, 
p. 127, pi iv, fig. 1), from the Clypeus-grit of Rodborough Hill is probably another 
variety. 
Boukgdetia, Section 2, the conventional Phasianella. 
Shell medium-sized to small, oval, conical-turrited, usualhj few-whorled, solid. 
Whorls smooth, usually convex, and for the most part devoid of ornament, save faint 
traces of lines of growth, suture simple. Body-whorl large and sometimes ventricose. 
Aperture oval, rounded in front, and scarcely angled posteriorly ; outer lip curved 
and full. 
The above diagnosis embraces what seems a natural group. It has been 
suggested that, out of the numerous forms in the Jurassics which have been 
referred to Phasianella, all may not belong to the same genus. This argument 
will scarcely apply to the group figured on PL XIX. These shells must hang 
together, whatever be the name or systematic position of the genus to which they 
are assigned. 
It has already been stated that the genus Oonia, Gemmellaro, appears to fulfil ' 
the required conditions. But, although some of that author’s figures greatly j 
resemble our Phasianellas, there are considerations which preclude our accepting 
the name Oonia for the group now under consideration. The diagnosis of Oonia | 
is somewhat meagre, but the strise of growth are stated to be sinuous, and it is , 
regarded as a section or subgenus of Pseudomelania. The sinuous growth- ' 
