File:The Quarterly journal of the Geological Society of London (12981233873).jpg

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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. .Feb. 23,
very much so. There is another point of resemblance in the slight
expansion only of the second pair of pleurse, the appearance being
rather as if the third pair were abbreviated than as if the second were
at all lengthened.
Lastly, one of the specimens shows what is rarely met with
among Trilobites, namely, an injury or malformation — ^the sixth and
seventh pleurae on the left side being shortened by the injury.
'Next I have to notice the occurrence of a very interesting fossil,
brought to England by Dr. Peuchtwanger, and placed with numerous
other American fossils in the Great Exhibition of 1851. It is a cast
in a brown sandstone, said to be a bouldered fragment from Georgia,\
and as the species appears to be distinct from any previously de-
scribed, there seems no reason to doubt the locality. The caudal
shield and part of the body are broken away, but the greater part of
the carapace, and ten body-rings remain. It is about the size of
Conocephalus striatus from Bohemia, and may be called —
COKOCEPHALXJS ANTIQFATUS, SpeC. UOV. (Fig. 2.)
C. sesqmuncialis, conrexus, glabella parabolica lobis inconspicuis ; genis vix
radiatis, oculis medianis glabellam propioribus, segmentis corporis pleuris cur-
vatis, baud abrupte deflexis.
Head (or carapace) semicircular, convex compared with those of
other species, the glabella somewhat parabolic and rounded, not
truncated in front, nor much expanded below. It is convex, and
the lobes are very obscure (the specimen, however, has suffered
abrasion); the lower pair of lobes are
rounded, the middle pair of furrows remote
from these, and the upper ones, very near
the anterior end, aU but obliterated.
Cheeks convex ; the eye nearly midway,
and about its own length from the posterior
margin. Keck-furrow distinct, not very
strong. Facial sutures as in C, striatus ;
the convex cheeks radiated, less conspi-
cuously so than in that species. The
ocular ridge, if any existed, must have
been very slight.
The axis of the body- segments is convex
and narrow, two-thirds the width of the
pleurae, which are gently convex, scarcely
flat even as far as the fulcrum, and thence
curved down, not abruptly bent as in C,
striatus. The fulcrum in the forward rings
is placed more than halfway out, — in the
tenth about halfway, and the furrow which
bisects the pleura is shallower than in either
of the Bohemian species.
The characters which distinguish C. antiquatus from C. striatus,
which most resembles it, may be briefly stated: — 1. The greater
convexity of the carapace, especially the glabella, which is long and
Fig. 2. — Outline-sJcetch
of Conocephalus an-
tiquatus (Salter).
(Natural size.)
The hinder portion of the
body and the right cheek