418 GASTEROPODA OF THE INFERIOR OOLITE. 



356. Pleurotomakia Stoddarti, Tawney, 1873. Plate XXXVI, fig. 2. 



1873. Pletjeotomabia Stoddakti, Tawney. Dundry Gasteropoda, p. 50 (42), 



pi. iii, fig. 5. 



Description : 



Height (full size) . . . .70 mm. 



Basal diameter . . . .84 mm. 



Spiral angle ..... 75°. 



Shell conical, subacute, largely umbilicated. Spire regular. Whorls (nine) 

 very convex, and curving each way towards the deep suture. The ornamentation 

 consists of spiral lines and oblique decussating radial lines inclined, as usual, in 

 opposite directions on either side of the sinus-band; the earlier whorls have a 

 cancellated appearance, but in the later ones the area above the sinus-band is 

 almost smooth from the absence of spiral lines and the faintness of the cross- 

 hatching. 



The sinus-band is broad and situated very slightly below the middle of the 

 whorls ; where these possess much ornament, it exhibits three spirals which are 

 cross-hatched ; in the later whorls it is flat and strap-like. The body- whorl is 

 tumid and rounded at the periphery ; base rounded, full, and almost smooth, or 

 only marked by curved radii springing from the deep and funnel-shaped umbilicus. 

 Apex subovate. 



Relations and Distribution. — As an obvious member of the Fasciat a-gro up this 

 is most nearly related to PI. subplatyspira, especially in the failure of ornament in 

 the upper part of the whorls. But the wider spiral angle, convex whorls, and deep 

 suture, serve to separate it. Viewed as a member of Deslongchainps' compound 

 species, Gyrocycla, it most nearly approaches the var. saccata, but has a much wider 

 spiral angle, besides other differences. 



Apparently known only from Dundry, where the Iron-shot Oolite has yielded 

 the Bristol Museum two fine specimens. 



357. Pleurotomaria amata, d'Orbigny, 1854. Plate XLIV, figs. 11 a, 11 b, lie. 



L854. Pleueotomaria amata, d'Orbigny. Terr. Jur., vol. ii, p. 512, pi. ccexcix, 



figs. 6—10. 



The principal objection to this identification arises from the circumstance that 

 d'Orbigny regarded his species as approaching PI. unisidcata. This is certainly 



