14 SUPPLEMENT TO GREAT OOLITE MOLLUSCA. 
Cuemnitzia vi7Tata, Phil., sp. Tab. XXXI, fig. 10. 
Meranta vitrata, Phil. Geol. York., p. 116, pl. 7, fig. 15: 
Cuemnitzia vitTata, D’Orb. Prodr., xi, et No. 29, p. 208. 
= — Mor. Cat., 2nd edit., p. 242. 
— — Oppel. Juraformation, p. 479. 
Testa crassa, turrita, elongata, apice acuto, anfractibus (circa 10) latis, in medio sub- 
depressis, ad suturas elatis, carinis duobus instructis, suturis valde depressis ; apertura, 
ovata bast angustata. 
Shell thick, smooth, turreted, elongated, apex acute; volutions (about 10) wide, rather 
depressed in their middle parts, elevated both above and beneath near to the sutures, 
forming two narrow, equal, cord-like carinze ; the sutures are deeply impressed ; the aper- 
ture is ovate, rather small and contracted towards the base, where the extremity of the 
columella is conspicuous ; the last volution is rendered somewhat angulated by the promi- 
nence of both the encircling carine ; the surface is shining, with large plications of growth ; 
a magnifier also discloses delicate, nearly regular, distantly arranged, encircling, granu 
lated lines (about 20 to a volution), or when the surface has been slightly abraded, they 
appear as punctated striations. 
Length, 43 inches; transverse diameter of the last volution, 1 inch; the height of each 
volution is equal to 3-5ths of its transverse diameter. 
The general figure is that of a lengthened cone, and the outline does not exhibit that 
step-like figure seen in some other allied species, as in Chemnitzia turris (Desl.), C. coare- 
tata (Desl.), and C. condensata (Desl.). The two narrow and equally elevated cord-like 
cinctures which bound each yolution, together with the somewhat angular figure of the last 
volution, separates it from the foregoing and all other known examples of the genus; 
perhaps the encircling granulated lines may also constitute a good distinctive character 
but it can only be discovered in very well preserved specimens. A Chemunitzia, in the 
Inferior Oolite of the Cotteswolds and of the south-western counties, which does not 
appear to have been figured or described, approaches near to C. vittata, and has sometimes 
been regarded as identical with it; there can, however, be no difficulty im separating 
specimens of the two forms, when they are well preserved. The Inferior Oolite shell is 
somewhat less conical, or more subulate ; the sides of the volutions are more flattened ; the 
upper cincture is rounded and distinct, but comparatively small; the lower cincture is 
angulated, and not cord-like ; the last volution is destitute of the prominent lower cincture, 
which imparts an angularity to that part in the Cornbrash shell; the general figure of that 
volution is more lengthened and pyriform, so that the base of the aperture is wider and 
more produced. The Inferior Oolite shell also does not exhibit any trace of the encircling 
granulated lines; but possibly the test has not been preserved with sufficient delicacy to 
