PLEUROTOMARIA. Al5 
Relations and Distribution.—The oblique and sinuous radial ornamentation in 
the upper part of the whorls resembles that which characterises both Pl. sulcata and 
Pl. Agathis. But the conical outline and sharper apex distinguish it from both 
these species. The general form is undoubtedly near to Pl. wnisulcata, though 
somewhat too uniformly conical, and the whorls not sufficiently angular. 
I have six specimens from the Humphriesianus-zone of Louse Hill and Oborne. 
The exact locality of the figured specimen is unknown (? Louse Hill). The form may 
be regarded as representing PI. sulcata, Sow., on a higher horizon, and very nearly 
equivalent to Pl. wnisulcata, d’Orb. 
353. PLevroromaria (? Leptomaria) Amyntas, d’Orbigny, 1850. Plate XX XV, fig. 12. 
1850. Prevroromarta Amyntas, @’ Orbigny. Prod., i, p. 268, 
1854. — — — Terr. Jur., vol. ii, p. 495, pl. 
ecexcil, figs. 6—10. 
1873. —_— 7 — Tawney, Dundry Gasteropoda, 
p- 41 (33). 
Description : 
Height : ; : : . 44 mm. 
Basal diameter : : : . 44mm. 
Spiral angle . ‘ ; , oa. 
Shell smooth, conical, subelongate, with a deep but narrow umbilicus. Spire 
regular and sharp, with the apex rather flattened. Number of whorls about 
nine in fully-developed specimens, though eight is more usual; these are sub- 
angular and moderately convex. The ornaments are usually very fine; in well- 
preserved specimens it is seen that the spiral striz in the apical whorls are crossed 
by fine axial lines, so as to be subreticulate; later, the spiral ornamentation 
becomes feeble ; the body-whorl in most specimens is nearly smooth, though in 
some (such as the one figured) the spiral ornaments are still visible. 
The slit is narrow, and extends backwards about a quarter of the circumference 
of the body-whorl. The sinus-band is narrow and smooth, being situate on the 
angular prominence of each whorl, so as to constitute a slight keel about two- 
thirds the way down. The body-whorl is usually smooth and bluntly angular at 
the basal periphery, the base flat, and glabrous or substriated; umbilicus funnel- 
shaped. Aperture suboval. 
Relations and Distribution.—This fine and often glabrous shell has affinities 
with the typical Leptomariz through its narrow sinus or slit; whilst the size and 
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