282 GASTEROPODA OF THE INFERIOR OOLITE. 
might almost be described as a variety. Besides being very much smaller, this 
form is less turbinate and more conical than Amb. ornata ; the posterior spiral is 
rather more strongly developed, and the tuberculation generally somewhat larger 
proportionately. It is common in the upper beds of the Lincolnshire Limestone 
at Weldon, Ponton, &c. A somewhat similar form occurs in the Inferior Oolite 
of Hook Norton. 
211. AMBERLEYA DENSINODOSA, sp. n. Plate XXII, figs. 3, 4, 5. 
Cf. Lirroriva sprnutosa, Miinst., sp. Héb. and Desl., Foss. Montreuil-Bellay, 
p. 56, pl. iii, fig. 4. 
N.B.—There has been a tendency to regard the form now under consideration 
as the representative of Turbo spinulosus, Minster. It has some resemblance to 
the fossils figured by Hébert and Deslongchamps, but as the differences appear to 
be considerable it may be safer to describe it as a distinct species. 
Description : 
+ 
Length (three specimens) : . 23, 35, and 43 mm, 
Length of body-whorl to total height . 48 to 52: 100. 
Spiral angle : : 7 OK 
Shell turbinate, eucycloid, turrited. Number of whorls, eight or nine, convex 
and subangular; sutural space very wide. The ornaments consist of four finely 
tuberculated spirals; the uppermost of those near the suture consist of a circlet 
of closely-set rounded tubercles; the second spiral is a tuberculated belt, the 
tubercles being small and rounded; the third and fourth spirals constitute the 
principal carine, the third usually having the strongest tuberculations; the 
interspiral spaces are marked by closely-set interspiral strie. The ornamentation 
of the matured whorls is generally finer than that of the earlier stages. 
The body-whorl is almost ventricose and similarly ornamented, the number of 
finely-granulated spirals in the base being seven or eight. In the adult shell the 
aperture is subcircular, with a short, straight, columellar lip, forming a slight 
angle anteriorly. In the younger shells (fig. 5) the Purpuwrina-like character of 
the aperture is more obvious. ; 
Relations and Distribution.—Distinguished from all varieties of Amb. ornata by 
a somewhat larger spiral angle and more turbinate whorls, and by the number 
and fineness of the ornaments. The variety from the Irony Nodule-bed of 
Burton Bradstock (fig. 3) is longer, narrower, and with a more gaping suture 
than specimens from the concavus-bed of Bradford Abbas, where Amb. densinodosa 
is somewhat sparingly distributed. A stout variety occurs at Dundry. 
