BULLA. 481 
433, CyLINDRITES cYLINDRIcUS, Morris and Lycett. Inferior Oolite variety. Plate 
XLIII, figs. 16a, 160. 
In this form the upper margin of the last whorl slopes slightly inwards, and 
encloses the spire-whorls within the depression thus formed, so that even the 
central mammilla is sunken. 
The figured specimen is thought to be from Nailsworth. It is preserved in 
the Inferior Oolite collection of the Jermyn Street Museum, and is the only one 
I have ever seen from that formation. 
Fanily—BULLIDA. 
* Shell globular or cylindrical, convoluted, thin, often punctate-striated ; spire 
small or concealed ; aperture long, rounded and sinuated in front, lip sharp.’—S. P. 
Woopwarp. 
The few representatives of this family (now broken up into Bullide, Aceride, 
and Aplustridz) in the Inferior Oolite may provisionally be retained under Bulla 
without prejudice to their being recognised as Hydatina or Acera. 
Genus—Butta, Linneus, 1758. 
434, Butta Favret, Lycett, 1857. Plate XLIII, fig. 10. 
1857. Burta Favret, Lycett. Cotteswold Hills, p. 125, pl. iv, fig. 7. 
Description.—Height 36 mm., width 28 mm. 
Shell ovate, ventricose or pyriform, summit contracted, and partially concealing 
the inner whorls, the first of which is slightly elevated. The columellar lip is 
drawn out anteriorly and sinuous. Aperture widely ovate anteriorly, and but 
moderately contracted posteriorly. 
Relations and Distribution.—The mammillary apex and extension of the 
columella easily serve to separate this shell from Bulla undulata, Bean. Indeed, 
they may be generically distinct. A single specimen from a high horizon in the 
Spinosa-stage near Avening, a village not far from Minchinhampton. 
