258 
Sorizon and Localities. — A single incomplete specimen was found in 
tlie sandstone at Eaymond Terrace. Mr. E. Etheridge, Jun., found it in a 
greyish limestone near Edinburgh. 
Pleurotomaeia naticoides, L. G. de Koninch. 
PL XXIII, Pig. 10. 
JPleurotomaria naticoides, L. G-. de Koninck, 1843, Descr. Anim. Poss. Terr. Garb. Belg., 
p. 405, pi. 31, fig. 8. 
,, ,, Idem, 1873, Eecb. Anim. Poss., II, p. 101. 
This shell is suh-discoidal, of medium size, with a flattened spire 
composed of seven or eight whorls, rather strongly keeled. That part not 
covered by the various whorls is strongly depressed and very slightly convex. 
Two-thirds of the upper surface are smooth, while the lower third is ornamented 
with small, slightly arched, radiating striae, arising from the suture. The 
narrow and projecting band of the sinus remains visible on all the whorls 
following the suture. The upper part of the last whorl of the spire is very 
convex. The umbilicus is broad and funnel-shaped. The aperture is transverse 
and sub-rhomboidal, and its slit is rather deep. 
Dimensions. — This shell never attains a great size, its length rarely 
exceeding one centimetre, while its breadth reaches three. Its spiral angle is 
about 130°. 
Relations and Differences. — It differs from P. expansa, Phillips by 
its much more discoidal form, and its relatively greater length. 
Dorizon and Localities. — I have found this species in the Upper 
Carboniferous Limestone of Vise, where it is rare. Mr. Clarke found a single 
specimen of it at Harper’s Hill. I have found it among the fossils of Bleiburg 
in Carinthia, and Mr. J. Thomson obtained it near Glasgow. 
Pleurotomaria helicin^eormis, P. G. de Koninch. 
PL XXIII, Pig. 13. 
This is a small, sub- globular shell, nearly as long as broad, composed 
of five convex spiral whorls, with a rather deep suture. The last whorl of 
the spire is relatively well developed, and has a slightly projecting band in 
