GASTEROPODA. 73 
CrossosToMA? piscorpEUM. Plate XI, figs. 7, 7a, 70. 
C. Testé levi, depressd; spird prominuld; anfractibus angustatis, suturis impressis ; 
apertura parvd, suborbiculari. 
Shell smooth, depressed; spire but little elevated, or nearly flat; whorls narrow, the 
sutures distinct ; aperture small, basal nearly round. The height is equal to half the basal 
diameter. 
This is, probably, only a variety of C. Praéfii, and in a state in which all our Great 
Oolite specimens occur—the outer lip not being quite entire, and extremely thin and 
slightly rugged, never perfecting a well-defined lip (C. discoideum); the change to the 
ultimate condition occupies a space which does not exceed one fourth of a volution, a 
few rugged lines of growth are formed; an irregular lamina next protrudes, forming a kind 
of frill around a contracted, thickened, and orbicular aperture, as in C. Pratti?. 
Locality. Minchinhampton Common and Bussage, at which places it occurs somewhat 
rarely, and in more than one of the shelly beds. 
CrossostoMA? HELICIFoRME. Plate XI, fig. 8. 
C. Testé levi, turbinatd, subdepressd; spird parvd prominuld; anfractibus conveai- 
usculis; aperturd ellipticd. 
Shell smooth, turbinated, somewhat depressed ; spire small, but little elevated ; whorls 
rather convex ; aperture elliptical. 
Locality. It is somewhat rare; our specimens have been obtained from the planking 
of Minchinhampton Common ; it is likewise found in the middle division of the Inferior 
Oolite at Leckhampton, near Cheltenham. 
This species has the general form of C. discordeum, but the spire is more elevated ; 
they are only provisionally referred to Crossostoma, having somewhat the aspect of Jono- 
donta, and even (in C. discoideum), the thickened base of Rotella. 
PHASIANELLA, Lam. 1812. 
Shell oval, smooth; aperture oval, entire, forming an acute angle posteriorly at the 
junction of the columella and outer lip; outer lip thin; inner lip spread over a portion of 
the columella. 
The Great Oolite shells provisionally referred to this genus are small, and like their 
recent congeners, individuals of the same species offer a considerable variety of form, which 
makes their determination rather difficult. 
