CRUSTACEA. 145 



imbricating strise, two-thirds concealed in front of the gla- 

 bella, ending posteriorly in acute spines as long as the glabella ; 

 neck-segment broad ; pijgidium 6 lines long and 7^ lines wide ; 

 axal lobe 2 lines wide, cylindrical, slightly tapering, of sixteen 

 rings, each ornamented with about ten lengthened oval tuber- 

 cles ; lateral lobes depressed, of ten broad, flat divisions, each 

 having a fine impressed line running close to its posterior 

 margin, smooth to the naked eye, but with a strong glass one 

 or two rows of minute crowded granules are seen ; margin 

 wide. 



The axal lobe of the pygidium being strongly tuberculated and 

 the lateral lobes nearly smooth, distinguish the species from all 

 other carboniferous Trilobites I know of. It is allied to the 

 G. calcaratus (M'Coy) and G. longispinus (Portk.). 



Common in the shales of the carboniferous limestone of Der- 

 byshire. 



{Col. University of Cambridge.) 



Cryphceus {Eccoptochile) Sedgwickii (M^Coy). 

 Sp. Char. Cephalic shield subsemicircular ; glabella sKghtly cla- 

 vate, smooth, three segmental furrows on each side, the pos- 

 terior pair longest, turning backwards and inwards nearly to 

 the neck-furrow, inclosing a triangular space on each side 

 longer than wide, the width rather less than that of the undi- 

 vided portion of the glabella between their bases, the two an- 

 terior pair of furrows shorter; cheeks broad, gently convex, 

 closely and coarsely pitted : thorax, axal lobe very convex, narrow, 

 slightly tapering, nearly parallel-sided, smooth, of twelve seg- 

 ments, three similar ones belong to the pygidium, the termi- 

 nal one being obtusely trigonal ; the side lobes are flattened, 

 and more than double the width of the axal lobe ; pleura, nearly 

 straight, narrow, and for the greater part of their length flat- 

 tened, and having a broad, nearly mesial pleural sulcus deeply 

 punctured like the cheeks, dividing each into two parts, the 

 posterior largest and forming a thick, smooth, rounded ridge, 

 bent down and a little backwards in the distal third of its 

 length, swelling to a thick narrow ridge in the middle, the 

 sides and extremity expanding into a broad, thin, foliaceous 

 appendage ; the pygidium terminates in six broad ovate, leaf- 

 like, semimembranous flaps. Length of thorax and pygidium 

 2 inches 2 lines, width 2 inches 3 lines, width of axal lobe 

 6 lines. 



This magnificent Trilobite can only be confounded with the 

 Eccoptochile clavigera (Beyrich sp.), from which it is distin- 

 guished by the much greater width of the lateral lobes of the 

 thorax, and the thin, flat, leaf-like appendages of the pygidium, 



K 



