﻿Vol. 66.] THE CAMBEIAX ROCKS OF COMLET. 45* 



The evidence available for description is meagre, and the- 

 following is necessarily an incomplete diagnosis. 



Cephalon. — Semi-oval, moderately convex, features in slight 

 relief. Glabella, proportionately long and wide, outlined by a> 

 decided but not deep axial furrow. Glabellar furrows slightly 

 impressed or wanting. Occipital furrow complete, wide and shal- 

 low. Occipital ring plain, or produced to a spine. Fixed cheeks 

 wide, gently and evenly convex, continuous with the frontal limb. 

 Eye-lobe long, distant from the glabella, low in elevation, not raised 

 at the edge. Ocular ridge slight or wanting. Postero-lateral 

 limb geniculated about half way out. Facial suture short and 

 direct, both forwards and backwards. Anterior margin with narrow 

 indistinct fold, or none. Free cheek small, pointed, or spined. 



Thorax and pygidium. — Unknown. 



MoHlCANA LATA, Sp. n0V. (PI. VI, fig. 4.) 



Only one specimen [578] is confidently referred to this form at 

 the present time. 



Crantdium : Size — moderate ; length = about 13 millimetres. 



General form. — Semi-elliptical, approaching semicircular ; pro- 

 portion of length to width = about 4:5. 



General convexity. — Moderate; but, owing to the very slight 

 relief of the features, there is an appearance of flatness. Speaking 

 generally, there is one uninterrupted sweeping curve from the 

 front and sides to the top of the glabella. 



Glabella. — Wide and flattened; parallel-sided, with rounded 

 apex ; distinct from the occipital ring ; no transverse furrows seen. 



Occipital furrows. — Wide, shallow, and entire. 



Occipital ring. — A plain band with curved margin; as wide 

 as the glabella ; no spine or tubercle. 



Axial furrow. — Wide and shallow ; continuous round the 

 apex of the glabella. 



Fixed cheeks. — Narrower than the glabella; gently convex ;; 

 most elevated 'close to the glabella; continuous with the frontal 

 limb ; falling rather steeply to the eye-lobe, which stands away 

 from it horizontally. 



Eye-lobe. — Half as long as the glabella ; almost reaching the 

 postero-lateral furrow ; situated at a low level on the head-shield ; 

 horizontal in transverse section. The specimen figured [578] has 

 now lost the eye-lobe, but it is still to be seen in the external cast, 

 from which, and from an earlier drawing, it has been reproduced in 

 the enlargement. 



Ocular ridge. — None seen. 



Posterior border. — A more or less triangular area with a 

 wide groove next the cheek, and a raised and rounded rim at the 

 margin, geniculated about halfway out. 



Frontal limb. — Gently convex downwards; no marginal rim 

 is preserved in the specimen. 



Facial suture. — Not actuall}* seen; there is no room, how- 

 ever, for anything but a fairly direct and short branch forwards, 



