92 FAUNA OF THE CORNBRASH. 



having a fairly wide umbilicus. The aperture is round except at its junction with 

 the previous whorl, but it is irregularly diminished by an apparent thickening. 

 From Scarborough. In the Sedgwick Museum. 



Relations. — The genus of this shell seems very doubtful. In some respects, no 

 doubt, it has a general resemblance to Trochus angulatus of Groldfuss (not Sowerby), 

 under which name it has been recorded ; but it has not a lower band and second 

 keel beneath it. Its aperture seems to point to Delphinula or some ally of that 

 genus. It requires some better preserved specimen or other confirmation to decide 

 its position. 



Genus ATAPHRUS, Gabb. 



Characterised by the smoothness of its whorls, the rounded off character of its 

 apex, and particularly by the sudden ending off of the thickened columella and 

 the replacement of a furrow in its continuation within the compass of its aperture. 



Ataphrus halesus (D'Orbigny). Plate VIII, fig. 21. 



1853. Trochus halesus, D'Orbigny, Pal. Fran*;. Terr. Jurassiques, vol. ii, p. 292, pi. cccxviii, figs. 1 — 4. 

 1860. — helms, Hebert and Deslongchamps, Bull. Soc Linn. Norm., vol. v, p. 218, pi. ix, fig. 5. 



Type. — " Shell conical, a little longer than broad, not umbilicated. Spire with 

 a slightly concave angle composed of flat, very smooth, whorls, the last whorl 

 with little convexity and smooth above, very angular at the circumference. Mouth 

 depressed, square, strongly encrusted on the columellar side, but without forming 

 teeth." 



Description. — The figured specimen has a rounded apex and smooth sides. 

 The spire as a whole and the last whorl are almost concave. The spiral angle is 

 about 70°. The lines of growth are exceedingly regular and fine. The basal border 

 line is somewhat swollen, the angle at the bend being rounded. The base appears 

 smooth but has exceedingly fine spirals. The aperture has the generically charac- 

 teristic feature well shown. There is a needle-point perforation to represent an 

 umbilicus (not seen in a second example). Length 10 mm., greatest breadth 

 10 mm. 



Distribution. — The figured specimen comes from Woodford, near Thrapston, and 

 there is a larger one from Quinton, Northamptonshire. Both are in the collection 

 of Mr. Beeby Thompson. 



This species is recorded as common at Boulogne. 



Relations.— D'Orbigny describes two species, T. halesus and T. helins, which 



