284 



Chbirukus Vulcanus. (N. sp.) 



Fig. 271. 



Fig. 2?!. — Cheirurus Vulcanus. a, side view of the glabella ; b, upper side of the 

 head ; c, a pygidium found along with a and b. 



Description. — Glabella in large specimens exceedingly convex, some- 

 times abruptly elevated just in front of the neck furrow. The contour is 

 ovate or obtusely conical, rounded in front and sides gently convex, a 

 little narrower in front than behind. Neck furrow extending all across ; 

 posterior pair of glabellar furrows with a sigmoid curve, originating in 

 the dorsal furrows a little behind the mid-length of the head, then sloping 

 gently backwards with a curve which is concave towards the front in the 

 lower half and convex in the upper half, the inner extremities separated 

 by about one-fourth the width of the glabella. The two anterior pairs are 

 one third the width of the glabella, and are both convex towards the front. 

 Cheeks small and drooping, rounded at the angles with a narrow slightly 

 elevated rim, which runs round the front of the glabella. Eyes very 

 small and close to the side of the glabella, opposite the front part of the 

 posterior glabellar lobe. 



Length of the largest glabella seen including neck segment 10 lines ; 

 width at the neck segment 8 lines ; elevation in the middle 5 lines. 



Surface with numerous small rounded tubercles ; the casts are usually 

 smooth. 



The pygidium associated with the fragments of the head of this species 

 is depressed convex, with a triangular axis ending in a point backwards, 

 with four transverse grooves, and three broad depressed convex ribs on 

 each side, the last two parallel with the median line and the others nearly 

 so. 



Locality and Formation. — P, Cow Head, Newfoundland ; Quebec 

 group. 



Collector. — J. Richardson. 



