422 



GASTEROPODA OF THE INFERIOR OOLITE. 



363. Pleurotomaria Allica, d'Orbigny, 1850. Plate XXXVI, figs. 5, 5 a. 



1850. Pleurotomaiua Allica, d'Orbigny. 

 1854. — — — 



1873. — — — 



Prod., i, p. 268. 



Terr. Jur., vol. ii, p. 490, pi. cccxc. 

 Tawney, Dundry Gasteropoda, p. 42 

 (34). 



55 mm. 

 45 mm. 



. 48°— 52°. 

 "Whorls (about nine) 

 There is some differ - 



Description : 



Height (large specimen) 



Basal diameter 



Spiral angle .... 



Shell conical, elongate, not umbilicated. Spire regular 

 flat to subconvex, and slightly projecting over each other, 

 ence of ornamentation between the apical and anterior whorls ; generally tbe 

 system may be described as consisting of rather wide-apart spirals above the sinus- 

 band, with a stronger and more decussated pattern below, i. e. the anterior portion 

 of each whorl is minutely cancellate down to the sutural margin. 



The sinus-band is median or only slightly anterior, fairly prominent in the 

 apical whorls, flattish and not very wide in the more advanced ones. The body- 

 whorl is between one third and one half the total height, and bluntly angular at the 

 periphery ; base flat to subconvex, with distinct spiral ornament and no umbilicus. 

 Aperture subquadrangular and moderately oblique, with a very thick columellar lip. 



Relations and Distribution. — PL Allica must be regarded as a member of the 

 Fasciata -group, having a narrow spiral angle and a comparatively small habit. 

 Its relationship to PI. Alimena is obvious. 



Tawney mentions one specimen from Dundry ; I have five from the Louse 

 Hill beds, which are generally regarded as in the upper part of the Humphriesiaiius- 

 zone. 



364. Pleurotomaria sdbreticulata, d'Orbigny, 1850. Plate XXXVI, figs. 6, 6 a, 



and ? fig. 7. 



1850. Pleurotomarta subreticulata, d'Orbigny. Prod., i, p. 268. 



1854. — — — Terr. Jur., vol. ii, p. 494, 



pi. cccxcii, figs. 1 — 5. 



1873? — — — Tawney, Dundry Gastero- 



poda, p. 46 (38), pi. iii, 

 fig. 7. 



Syn. — reticulata, Deslongchamps. Vol. cit., p. 64, pi. ix, fig. 3. 



