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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 

 have been restored. 



