MURCHISONIA. 
319 
undoubtedly belong to the same species, and are characterised by the central 
convex sinus-band, the peculiarly arched sides, and the numerous spiral striae. 
Affinities. — From M. turhinata, Schlotheim, this species is widely separated, and 
evidently is formed on a very different plan. M. trepomena approaches it more 
nearly ; from Phillips' original figure it might perhaps be supposed to be identical, 
but his description and an examination of the type specimen show that it is really 
quite distinct. In that species the sinus-band is not central but close to the 
lower suture, there were very few spiral threads in the ornamentation, and the 
contour of the whorls is nearly evenly conical. 
It approaches the Carboniferous M. angulata, Phillips, sp.,^ but, as seen by a 
comparison of Phillips' specimens in the British Museum, in that shell the whorls 
are broader, the spiral striae are smaller and more numerous, and the sinus-band 
does not seem so coarsely nodulated. 
6. MuECHisoNiA ? OBESA, n. sp. PI. XXX, fig. 21. 
Description. — Shell small, conical, turrited, moderately elongated, of six or 
seven narrow, regularly and slowly increasing volutions. Apex acute. Suture 
rather deep and broad. Whorls very narrow, gently and evenly convex, slightly 
flattened on the back. Sinus-band narrow, flat, situated about three-quarters 
down on the whorl, and below its greatest width. Body-whorl small, similar to 
the other whorls of the spire. Ornament consisting of very numerous, delicate, 
direct transverse striae, apparently tending slightly backwards just above the sinus- 
band and gently curving on it, crossed and decussated by numerous similar spiral 
striae, which seem larger and coarser on the lower part of the whorls. 
Size. — Height and width about 15 mm. 
Locality. — Wolborough. There are two specimens in Mr. Vicary's Collection. V 
Remarks. — These specimens are so much worn that the ornament and other 
characters of the shell cannot be fully made out. Whether the band on the lower 
part of the whorl is a true sinus-band is not absolutely certain, but as far as can 
be seen from the state of the ornament it has every appearance of being so. 
In general shape these little fossils are very different from any other Gasteropod 
occurring in the beds we are now reviewing, and I have not noticed any foreign 
species with which they appear to correspond. 
1 1836, Phillips, ' Geol. Torks.,' vol. ii, p. 230, pi. xvi, fig. 16. 
