PLEUROTOMARIA. 
289 
8. Plbubotomakia seminuda, n. sp. PL XXYIII, fig. 1. 
1840. PiEUROTOMARiA ciEEiFOEMis ? Sowerhy. Gcol. Trans., ser. 2, vol. v, pt. 3, 
pi. Ivii, fig. 17 (not Min. Conch.). 
? 1853. — OBENATOSTEiATA, Sandberger (para). Verst. Rhein. 
Nassau, p. 188, pi. xxiii, fig. 2 d (only). 
1854. — CIEEIFOEMIS, Morris. Catal. Brit. Foss., p. 272 
1888. — — Etheridge. Foss. Brit., vol. i, Pal. p. 164. 
Description. — Shell rather small, trochiform. Sph'e of four or more rapidly- 
increasing narrow whorls. Suture simple, horizontal, deep. Whorls bluntly 
triangular, spreading out obliquely with a slight convexity from the suture to their 
widest part, where they turn through a blunt angle, and then slope in for a short 
distance to the lower suture. Body-whorl large, uniform with the upper whorls, 
arching in below to form a wide flatfish base. Sinus-band situate on the 
widest part of the whorls, wide, concave, bounded by two large prominent 
rounded ridges or keels, of which the lower is the more prominent. Ornament 
consisting of a third indistinct keel a short distance below the sinus-band, and of 
coarse transverse ribs arching gently back from the suture, and recurved on the 
sinus-band. Umbilicus and mouth unseen. 
81^6. — Height 14 mm., width 14 mm. 
Locality. — Wolborough. There is a specimen in the Battersby Collection of 
the Torquay Museum, and another in the Woodwardian Museum. 
Remarks. — The above description is taken from the Battersby specimen, 
which is, unfortunately, in so poor a state of preservation that the ornamentation 
is almost entirely obliterated. It was evidently a beautiful shell. The sides of 
the whorls are flattened and expanding, being at first a little convex and then a 
little concave before they reach the sinus-band. 
As far as can be judged from the figure of Sowerby's cast, it is identical with 
his PI. cirriformis of the ' Geol. Trans.,' but it differs much from the shell 
previously described by him under that name in the ' Min. Conch, which is a 
finely cancellated shell of a different shape, and with a very differently arranged 
sinus-band. 
Affinities. — This shell approaches the shorter of Sandberger's two figures of 
PI. angulata, Phill. sp.,^ but it differs from it in having flatter and more angular 
whorls, and having the sinus-band narrower, and situated lower down on the 
1 1817, Sowerby, ' Min. Conch.,' vol. ii, p. 160, pi. clxxi, fig. 2. 
2 1853, Sandberger, ' Verst. Rhein. Nassau,' p. 204, pi. xxiv, fig. 19 (only). 
