368 GASTEROPODA OF THE INFERIOR OOLITE. 



Opalinus-zone, at Drympton, and from the lowest Murchisonse-zone at Bradford 

 Abbas and Halfway House. May be noted in the shell-bed below the Lower 

 Limestone at Crickley. It also occurs in the Dogger, and generally in those 

 portions which are below the Nerinaea-bed, being, on the whole, a fossil character- 

 istic of a low horizon. By the gradual rounding of the angles and refinement of 

 the ornaments D. angulata passes into the species next described. 



304. Delphinula (Turbo) granata, Hudleston, 1885. Plate XXX, fig. 17. 



1885. Tubbo (Delphinula) gbanattjs, Bean, MS. Hudleston, Geol. Mag., 



dec. 3, vol. ii, p. 55, pi. ii, figs. 9 — 12. 



Bibliography, Sfc. — In the description of this species, two varieties were noticed 

 by me. The first of these is more properly D. granata ; the second variety 

 probably shades off into D. angulata. 



Description : 



Length ..... 11*5 mm. 

 Width . . . . .14 mm. 



Spiral angle (variable) . . . 95°. 



Shell turbinate and umbilicate; spire rather more than one-third the total 

 height, but variable in this respect, the younger shells being the most depressed. 

 Number of whorls in the full-grown shell five, usually flattened towards the apex. 

 In those cases where the ornaments of the spire-whorls are preserved, tuberculated 

 spirals at the posterior and anterior margins may be noted, but very often adult 

 shells (as in the figured specimen) show scarcely any ornament in the whorls of 

 the spire. In the more gibbous varieties, where a portion of the base of the 

 penultimate is exposed through gaping of the suture, the whorl appears strongly 

 carinated. 



Body-whorl large, rounded to subangular and ornamented by a number of 

 tuberculated and granular spiral bands. There is generally a compound spiral 

 band on the posterior margin ; the widest part of the shell is marked by a slight 

 carina with conspicuous granulations, below which are other slight keels. The 

 base is very full and granulated, the spiral ornaments terminating in a circle of 

 tubercles round the deep and funnel-shaped umbilicus. Aperture as in the pre- 

 ceding species. 



Relations and Distribution. — This is so variable a species that scarcely any two 

 shells are alike. It is more rounded in outline, and the ornaments are of a more 

 granular character than is the case with the forms previously described. 



Fairly abundant in the Dogger, D. granata is elsewhere represented by allied 



