PLEUROTOMARIA. 437 
angle. The body-whorl is relatively very large, subdiscoidal, and convex, forming 
a blunt angle at the periphery ; this angle carries about three decussated spirals, 
nodose at the points of intersection. The base is tumid, and largely excavated by 
the funnel-shaped umbilicus; strong spirals are decussated by sinuous radii not 
extending quite to the margin. Aperture ovate-depressed, 
Relations and Distribution.—One of the most prominent features in this species 
is presented by the radial costs of the flat part of the whorls, and this hkewise 
is characteristic of the other varieties of Pl. Debuchii. 
My specimens are from the Murchisonx-zone of Chideock and Bradford Abbas, 
and there are smaller ones, with a rounder basal periphery, from the Concavus-bed. 
Rare. . 
A micromorph closely resembling Pl. platyspira, V@Orb. (= Pl. Debuchii, var. 
platyspira, Deslongch.), occurs in the Murchisonex-zone at Crickley. 
378. PLEUROTOMARIA MIRABILIS, Deslongchamps, 1848. Micromorph. Plate XX XIX, 
figs. 7a, 7b, 7c. 
1848. PxrevroroMarta MrRaBILis, Deslongchamps. Vol. cit., p. 31, pl. xvi, fig. 2. 
1854. —_ — —_ D’Orbigny, Terr. Jur., vol. ii, 
p- 433, pl. ceelvil. 
There are two specimens in my collection (one figured), which possess the 
characteristic euomphaloid shape, sunken spire, wide umbilicus, and general orna- 
mentation of this remarkable Middle Lias species. The ornaments on the upper 
side present some difference, being finer and less nodose. The specimens are small, 
the breadth averaging about 20 mm. Provisionally labelled Pl. ‘ submirabilis”’ ; 
there is scarcely sufficient material for constituting a new species. Believed to 
come from the Murchisonx-zone of Bradford Abbas. 
From the above it may be gathered that we have three Middle Lias species re- 
appearing in the Murchisonex-zone, viz. Pl. Mopsa, Pl. platyspira, and Pl. mirabilis ; 
the two latter as micromorphs. 
379. PLEUROTOMARIA SUBARANEOSA, sp. nov. Plate XXXIX, figs. 1a, 15. 
Description : 
Height (medium size) . : : . 38 mm. 
Basal diameter z , : . 45 mm. 
Spiral angle . : 5 : a) tei 
