126 J. Starhie Gardner — On the Oault Aporrha'idce. 



proportion to the wing, and the tubercles seem less elongated. They 

 occur usually in a crushed condition. 



Distribution. — This and A. marginata, Sow., are the most abundant 

 Gasteropods at Folkestone, ranging through all the beds of the Gault, 

 and being frequently found in masses together. Mantell, Fitton, 

 and others mention it from Eingmer, Eidge, Bletchingley, Laughton, 

 Norlington, Warminster (?), Cambridge, etc. 



On the Continent its distribution seems restricted to the Paris 

 basin, but many of the casts figured imder other names may, on 

 examination, be found to belong to this species, and its known 

 localities would be thus extended. The spire without the last whorl 

 or wing process may easily be confounded with A. marginata, and 

 in the form of casts they are still more difficult to separate. It is 

 eminently characteristic of the Gault. 



History. — This shell was first figured and described by Mantell as 

 Eostellaria carinata, in the Geology of Sussex, in 1822, p. 86, tab. 

 xix., figs. 12 to 14 ; again by Sowerby in Fitton, 1836 ; and by 

 D'Orbigny in 1812, who first published a tolerably perfect repre- 

 sentation of the species. It was next noticed in D'Orbigny's Pro- 

 drome. Pictet and Campiche did not figure this form, but it is 

 mentioned on page 621 in their list. In 1859 Dr. Chenu figured 

 it, page 259 in the Manuel de Conch., as Pteroceras carinata. Mr. 

 E. Tate in 1865 described it in the Geol. Eepertory, p. 97, fig. 17, 

 as an Alaria. It is the Gladius carinatus of Gabb, 1861. 



Considering its abundance, it is surprising that it should have been 

 noticed by so few authors, but it probably is owing to the re- 

 semblance of its spire and ornamentation to that of A. marginata. 

 The following may be identical with A. carinata or are closely 

 allied : — B. Pictetiana, de Loriol, 1861. Neocomien ; B elegans, id. ; 

 B. Neckeriana, Pict. and Eoux, Perte-du-Ehone, figured from casts. 

 PL tuberosa, Briart and Cornet, though greatly resembling A. 

 carinata, is probably distinct. 



Aporrhais elongata, J. Sowerby. Plate V. Figs. 2, 2a, 3. 

 Description. — Shell very elongated, spire forming an angle of 20°, 

 and consisting of nine or ten convex whorls, which are one and a half 

 times wider than high, finely striated spirally, and with ten or eleven 

 salient, rounded ribs, which extend across the entire breadth of the 

 whorls. Three or four of the strise are much more defined near the 

 apical suture, and form a narrow, distinct, flat region between the con- 

 vex parts of the whorls, thus giving a decided character to the shell ; 

 the ribs nearly disappear on the last whorl, which has a single in- 

 distinct keel. The wing is a long straight projection at right angles 

 to the axis; longer and narrower than that of A. carinata, which its 

 termination should resemble. I have seen no specimen more perfect 

 than the one I have figured, Plate V. Fig. 2 ; but John Griffiths, of 

 Folkestone, remembers finding one with a wing terminating " like 

 a pickaxe." This specimen, he thinks, found its way into Mr. 

 Wiltshire's cabinet. The outer lip is angular; the columellar lip 

 encrusted with the aperture, resembling A. carinata. The anterior 



