” 
Ne TRACHELIPODA. STOMATIA. 
a 
Ne 
below in a sharp point; pillar lip with a strong oblique 
fold at its centre. 
Monoptygma elegans. Plate VI. fig. 16. 
The shells of this genus are exclusively fossil, and have hitherto only been 
met with in the United States, North America. 
TRIBE IV.—MACROSTOMA. 
Shells auriform, with the aperture very wide, and the 
margin disunited ; destitute of a columella, or operculum. 
Genus LXI.— PLEUROTOMARIA. — De France. 
Generic Character. — Shell turbinated ; for the most 
part trochiform, usually abruptly conical, in others subtur- 
reted ; aperture generally subquadrangular, in other species 
somewhat rounded, considerably flattened, and largely um- 
bilicate at the base ; outer lip sharp edged, furnished with a 
deep notch at its upper extremity, near the suture. 
Pleurotomaria sculpta. Plate V. fig. 2; P. lirata, fig. 11. 
The Pleurotomarize having a much deeper fissure, and being destitute of a 
canal, at once distinguish them from the Pleurotome. In their general 
contour they nearly resemble the Trochide. 
The shells of this genus have only been found in a fossil state. Casts of 
them have been discovered in a stratum of limestone, in Normandy; and they 
occur in the Kimmeridge Shale, or Oxford Clay ; and in the Inferior Oolite. 
Genus LXII.—SCISSURELLA. — D’ Orbigny. 
Generic Character. — Shell with a depressed spire, con- 
sisting of few volutions; aperture nearly orbicular; lips 
separated from each other at the upper part on the left 
side ; outer lip sharp on the edge; an oblong foramen near 
the upper part on the right lip, conforming to the growth 
of the volutions, placed nearly parallel with the suture, and 
forming a sort of keel upon the back of the shell ; destitute 
of a canal. 
Scissurella concinna. Plate VI. fig. 17. 
The species of this genus are minute, and are chiefly found on the shores of 
the Mediterranean. One species, however, was found by Dr Fleming in sand, 
from Noss, Zetland, after a storm, viz. Scissurella crispa. 
They have been found fossil in the Calcaire-grossieér of Grignon, and in 
fossil sand at Castel Arquato. 
Genus LXIII.—STOMATIA.— Lamarck. 
Generic Character. — Shell suborbicular or oblong, 
generally ear-shaped and depressed ; pearlaceous within, 
aud usually coloured externally ; spire with from two to 
