398 



CONOCEPHALITES ZENKERI. (N. Sp.) 



Fig. 375. 

 Fig. 375. Conocephalites Zenkeri. 



Description. Length apparently abont two inches. Head very convex 

 nearly semi-circular, with a strongly elevated thin sharp margin all round - 

 the front and sides, and just within this a wide deep uniformly concave 

 furrow, the width of which is equal to about one third the length of the 

 glabella. The posterior margin is strengthened by the neck segment which 

 extends the whole width of the head, and becomes much elevated on ap- 

 proaching the outer angles. Glabella conical, very convex, most elevated at 

 about the mid-length, with a well defined neck furrow, the posterior lateral 

 furrows directed obliquely forwards at an angle of 45 with the longitudi- 

 nal axis of the body, their inner extremities separated from each other by 

 full one third the width of the glabella ; the posterior lobes sub-triangular, 

 their anterior angles situated at nearly one third the length of the glabella 

 forward excluding the neck furrow and segment; the middle lateral fur- 

 rows represented by a small depression or indentation on each side situated 

 on a line drawn across the head passing through posterior half of the eyes ; 

 in front of these a much smaller indentation on each side representing the 

 anterior furrows. The eyes are small and conical, situated on a line cross- 

 ing the glabella at one half the whole length of the head, their distance 

 from the glabella equal to one-third the width of the neck segment ; ocular 

 ridge extending from the eye forward to a point situated a little in advance 

 of the anterior lateral indentation or furrow of the glabella. From the eye 

 a strong ridge runs outwards to the margin of the head in two of the spe- 

 cimens, but in another it is not seen. Between the eye and the posterior 

 margin, and situated near the posterior lobe, on each side is a large sub- 

 semicircular tubercle. This elevation is very slight in the small specimens. 

 The surface of the glabella and cheeks adjacent thereto are apparently 

 smooth, but the whole of the concave border around the head is ornamented 

 with fine rugose striae distinctly visible to the naked eye. 



Length of head in largest specimen seen eight lines ; length of glabella 

 six lines; width of head fifteen lines ; width of glabella four lines ; distance 

 between the eyes six lines. 



