﻿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 Arab, 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. Ambeeleya densinodosa, sp. n. Plate XXII, figs. 3, 4, 5. 



Cf. Littoeina spinulosa, Munst., sp. Heb. and Desl., Toss. Montreuil-Bellay, 



p. 56, pi. iii, fig. 4. 



N.B. — There has been a tendency to regard the form now under consideration 

 as the representative of Turbo spinulosus, Minister. It has some resemblance to 

 the fossils figured by Hebert 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 . . . 58°. 



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 carinas, the third usually having the strongest tuberculations ; the 

 interspiral spaces are marked by closely-set interspiral striae. 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 Purpurina-like character of 

 the aperture is more obvious. 



Relations and Distribution. — Distinguished from all varieties of Ami. 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 N"odule-bed of 

 Burton Bradstock (fig. 3) is longer, narrower, and with a more gaping suture 

 than specimens from the concavus-hed of Bradford Abbas, where Amb. densinodosa 

 is somewhat sparingly distributed. A stout variety occurs at Dundry. 



