Contributions to Palaeontology. 



157 



Fixed cheeks flat, half as wide as the glabella. In the 

 larger specimens, a distinct ocular ridge extending from 

 the palpebral lobe in the direction of the front of the 

 glabella : posterior limb unknown. Frontal limb much 

 expanded, with a narrow flattened space beyond the 

 groove, and, rising abruptly, it spreads in a broad flat- 

 tened border which is apparently not thickened upon 

 its margin. 



A movable cheek in the same association is elongate 

 triangular, with a large ocular sinus : the posterior angle 

 is produced into a long curving spine ; the body of the 

 cheek is convex, with a wide flattened border. 



The measurements of the head are as follows : Length 

 of glabella anterior to the occipital furrow, 0-36 of an 

 inch ; width at base, 0*30 ; width at the anterior end, 0-24 ; 

 entire length of head, 0-61 ; frontal limb, 0*18 of an inch. 



A pygidium, fig. 21, found in the specimens from Marine mills, 

 ■which appears to be too large for any individual of C. oweni, I 

 suppose may belong to this species. It is more than twice as wide 

 as long ; the axis abruptly elevated, and marked by six annulations, 

 including the anterior one; the lateral lobes are nearly flat, and 

 marked by three divided ribs besides the anterior one, all terminat- 

 ing in a flattened border. A single specimen, larger than this one, 

 has been seen. 



PLATE II. 



Fia. 36. The glabella and part of the fixed cheeks, showing ocular ridges. 

 ( The specimen is of medium size, from Marine mills.) 



Fig. 37. A part of a larger head, with the glabellar furrows more strongly 

 marked. 



Fig. 38. A cheek associated with fig. 37, and probably of the same species. 



The figure shows the course of the facial suture and the exten- 

 sion of the border on the lower side, which reaches beneath the 

 frontal limb. 



PLATE III. 



Fig. 18. A glabella and frontal limb, in which the space between the front 

 of the glabella and the elevated border is much narrower than 

 in the other specimens. 



Fig. 21. A pygidium which occurs in the same association. 



