PLEUROTOMARIA 433 



374. Pleueotomaria oxytera, sp. nov. Plate XXXVII, fig. 6. 



Description : 



Height . . . . .35 mm. 



Basal diameter . . . .55 mm. 



Spiral angle ..... 92°. 



Shell conical, trochiform, moderately umbilicated. Spire regular or very 

 slightly concave ; apex sharp. Number of whor-ls about eight ; those at the apex 

 slope regularly, but presently become subgradate, sutures close and not cana- 

 liculate. The spiral system of ornament is strong, undulating, and rather wide 

 apart ; there is a diadem of regular and rather fine tubercles at the angle and 

 another at the base of each whorl, which is subbicarinate. 



The sinus-band is median, prominent, and pretty wide, but varies in the 

 different whorls ; showing from one to three spirals, though this feature is effaced 

 in the body- whorl, where it is somewhat flattened. The posterior area of the 

 body-whorl is mostly without tuberculation, but the lower keel is very prominent 

 and nodular, showing a strongly dentate periphery. Base convex, without marked 

 spiral ornament, deeply but not widely umbilicate, and very actinomphaloid, the 

 larger specimens being smoother. Aperture subrhomboidal and oblique. 



Relations and Distribution. — Distinguished both from PI. Actsea and PI. 

 actinomphala by its conical habit and sharp spire, it approaches the latter in the 

 character of its ornamentation, whilst the actinomphaloid base is a feature shared 

 by all three species. It is very directly connected with the acute variety of 

 PI. actinomphala, but the umbilicus is always smaller, and there are other 

 differences. 



I have three specimens from the Sauzei-hed, Oborne. 



375. Pleurotomaria actinomphala, Deslong champs, 1848. Acute variety, Plate 



XXXVII, figs. 7 a, 7 b, and Plate XXXVIII, 

 fig. 5. Obtuse variety, Plate XXXVIII, 

 figs. 1 — 4. 



1848. Pleueotomaria actinomphala, Deslongchamps. Vol. cit., p. 32, pi. xviii, 



fig. 1. 

 1854. D'Orbigny, Terr. Jur., 



vol. ii, p. 458, pi. ccclxxiv. 

 1873. Tawney, Duudry Gas- 



teropoda, p. 49 (41). 



