364 GASTEROPODA OF THE INFERIOR OOLITE. 



299. Delphinula (Turbo) Buckmanni, Morris and Lycett, 1851, Inferior Oolite 



variety. Plate XXX, fig. 11. 



1851. Delphinula Buckmanni, Morris and Lycett. Great Ool. Moll., pt. 1, 



p. 71, pi. v, fig. 8. 

 1884. Turbo Buckmanni, Morris and Lycett. Cossmann, fitage Bath., p. 265, 



pi. vii, fig. 50. 



Bibliography , fyc. — The authors speak of D. Buckmanni as occurring in the beds 

 of coarse planking on Minchinhampton Common, though it must be rare, as I have 

 never seen any specimens from the Great Oolite except the three in the Jermyn 

 Street Museum, one of which is the type. In none of these are there strong indica- 

 tions of an umbilicus. Quoted by Cossmann from two localities in the Bathonian 

 of France. 



Specimens from the Inferior Oolite show a considerable umbilicus. The 

 following relates exclusively to Inferior Oolite specimens, which may possibly 

 represent a distinct species. 



Description : 



Height . . . . .10 mm. 



Width . . . . .11 mm. 



Spiral angle ..... 80°. 



Shell turbinate, moderately thick, more or less umbilicated ; the spire, which is 

 pointed and conical, occupies about two-fifths of the total height. Number of 

 whorls five ; the two apical ones smooth, the next two are carinated anteriorly, 

 and ornamented with a pair of tuberculated spirals, the points of which are joined 

 by thick radial costse ; sutures moderately wide. 



The body- whorl is large, angular, and bicarinate; base full. The primary 

 ornaments consist of a tuberculated spiral on the posterior margin, and one on 

 each of the carinae, these being decussated by a system of thick radial costae, which 

 extend from the posterior margin of the whorls across the intercarinal hollow, and 

 right across the base to the margin of the funnel-shaped umbilicus ; fine spiral 

 striae, especially conspicuous in the intercarinal hollow, constitute a secondary 

 ornamentation. The aperture is circular, with but little callus on the inner lip. 

 The radial costae are sometimes continued over the margin of the umbilicus, which 

 varies as to size, being much encroached upon in some of the older shells. 



Relations and Distribution. — If this is really the same as the Great Oolite 

 species, the range of D. Buckmanni is considerable. In the Inferior Oolite it has 

 only been found, so far as I know, in the Oolite-Marl of the Nailsworth district, 

 whence specimens are occasionally obtained. 



