324 



Cheirurus Satykus. (N. sp.) 



Fig. 309. 



Description. — Glabella extremely convex, so much elevated as to 

 become obliquely conical, gradually passing upwards into a stout spine, the 

 base of which occupies the whole of the second one-fourth of the length 

 from behind. On a vertical view the outline is oblong, the length 

 two-sevenths greater than the width, the sides gently convex and 

 sub-parallel, the anterior corners nearly right angles, the anterior 

 margin moderately convex, and apparently with a very narrow 

 rim. There are three pairs of glabellar furrows ; the posterior pair leaving 

 the dorsal furrows at rather more than one-third the whole length from the 

 posterior margin, and sloping upwards and backwards until their inner 

 extremities approach each other within one-third of the whole width ; the 

 other two pairs are situated in the anterior half, and are very short. 

 The neck furrow extends all across, and the neck segment appears to 

 have a small tubercle in the middle. 



Length 2^ lines ; width 1| lines. 



Locality and Formation. — ^Chazy limestone, Montreal. 



Collector.— T. C. Weston. 



Cheirurus Vulcanus (««tc, p. 284). 



Fig. 310. 



Fig. Z\0.— Cheirurus Vulcanus. a, side view of a large glabella; 6, upper side of 

 another somewhat larger : c, side view of a glabella in which the pos- 

 terior part is extremely convex. 



Remarks. — Since the description of this species {ante, p. 284,) was 

 printed, a large number of specimens of the glabella have been collected 

 at Stanbridge. The form varies greatly. In some the outline is uni- 

 formly arched from the front margin to the neck furrow ; in others, the 



