88 GASTEROPODA OF THE INFERIOR OOLITE. 



Length of body whorl to entire shell . . 62 : 100. 



Spiral angle .... 63° 



Shell ovate-oblong, apex acute ; spire about fourth tenths of the entire shell. 

 Whorls five to six, angular, but the posterior area slopes outwards ; flanks scarcely 

 tumid. There are about sixteen rather thin longitudinal costa3, which in the 

 whorls of the spire are continuous, and form nodes at each of the keels ; they 

 also form nodes in the keel of the body-whorl, but die out anteriorly. The 

 cost® decussate with spirals which are wide apart, wavy in outline, and about 

 half the thickness of the longitudinals. This produces a regular network, of which 

 the mesh is largest spirally. Spiral ornamentation of a fine character is also trace- 

 able on the posterior area. 



Aperture very similar to that of P. elaborata, but with rather shorter columella. 

 Very slight trace of the umbilical slit. 



Relations and Distribution. — This pretty species has some resemblance to Purpu- 

 rina ornatissima, Moore (op. cit.), from the Marlstone of Ilminster. But in Moore's 

 species the phell is more ovate, the whorls are subtumid and very slightly tabulate. 

 The ornamentation of Moore's species more resembles that of P. elaborata. 



P. cancellata is described from a unique specimen in a very good state of 

 preservation. It is stated to come from Stoford, and has much the appearance of 

 a fossil from the Sowerbyi-bed. 



4. Purpurina bellona, D'Orbigny, 1850. Plate I, figs. 5 a, b ; 5 c, d ; 5 e,/. 



1850. Pubpurina bellona, D'Orbigny. Prod. 1, p. 270. 

 1852. — — — T. J., 2, pi. 331, figs. 1—3. 



1886. Non — - — Vacek, Fauna von Cap. S. Vigilio, p. 109, 



pi. 18, fig. 7. 



Bibliography, 8fc. — This is the regulation name for most Purpurinas from the 

 Inferior Oolite. I have already pointed out that D'Orbigny's type must have come 

 from the " Oolithe ferrugineuse," and is therefore a fossil of the Upper Division. 

 The species is capable of numerous subdivisions, some of which might almost be 

 raised to the rank of species. 

 Description : 



Length of a medium specimen . . .21 mm. 



Ratio of width to length . . 66 : 100. 



Length of body-whorl to entire shell . . 55 : 100. 



Spiral angle .... 60°. 



Shell ovate-oblong, turrited, apex acute. Spire nearly half the length of the 



