﻿271 MR. F. R. C. REED ON THE EATJNA OF [May I9IO,. 



Bathyurelltts glensatjlensis, sp. nov. (PI. XXI, figs. la-3b.) 



Head-shield convex, semioval to parabolic, with genal angles 

 produced back into stout pointed spines. Border strongly concave 

 and slightly upturned, broad in front, narrowing to genal angles,, 

 without definite marginal furrow. Glabella cylindro-conical, with 

 nearly parallel sides and with an obtusely-pointed anterior end, rising 

 above the cheeks with a gentle independent convexity, smooth, 

 without lateral furrows, in length equal to about two-thirds that of 

 the head-shield and in width to about a quarter of its width. Axial 

 furrows well marked, narrow, not deeply impressed, continuous round 

 the front of the glabella. Occipital furrow straight, narrow, of the 

 same strength as the axial furrows, marking off a broad, flattened, 

 simple, band-like occipital segment, in width equal to about a sixth 

 of the length of the glabella, Eye-lobes large, semicircular, a little 

 more than a third of the length of the glabella, situated rather far 

 back at less than their own length from the posterior margin of the 

 head-shield, with a breadth equal to about a quarter of the width 

 of the glabella. Facial sutures with the anterior branch curving 

 strongly outwards in front of the eye, and then forwards and 

 slightly inwards to cut the margin of the head- shield at an acute 

 angle at the level of the front end of the glabella, and at a distance 

 from it equal to more than double its width. Posterior branch of 

 the facial sutures short, curving backwards and outwards to cut the 

 posterior margin acutely at a distance about half way out to the 

 lateral edge of the head-shield. Anterior wings of fixed cheeks 

 broad, convex, uniting in a wide preglabellar area in front, and 

 arching down steeply into a broad concave border. Posterior wing 

 of fixed cheek small. Neck-ring flattened, of moderate width,, 

 marked off by a faint neck-furrow which disappears at the facial 

 suture. Free cheeks large, elongated, triangular, convex, with the 

 posterior outer angle produced backwards and tapering rather slowly 

 into a long genal point ; border concave, broad, narrowing and dying 

 out before the genal point. Eye rising steeply from the cheek, con- 

 stricted at the base, semilunate, rounded, convex, with its surface 

 composed of eighty to ninety diagonal rows of minute lenses, each 

 row containing about twenty lenses. Surface of occipital segment 

 ornamented by small, broken, somewhat sinuous, imbricating 

 lamellae, arched sharply forward in the middle. 



Dimensions. — Length of head-shield = 18 millimetres; width, 

 of middle shield between the anterior ends of the facial sutures := 

 22 mm. ; width of the same between the eyes = 12 mm. ; length of 

 glabella = 11 mm. ; width of the same at the base = 7 mm. 



This interesting trilobite is represented in the collection by two. 

 head-shields, one of which is fairly perfect, and by two free cheeks. 

 All the specimens come from the gritty tuff marked 62. 



In general shape the head is like that of Bathyurellas formosus, 

 Billings, 1 from the Quebec Group of Newfoundland, but the course 

 of the facial sutures is more like those in B. eccpansus, Billings, 2 - 



1 ' Paleozoic Fossils of Canada ' vol. i (1865) p. 266 & fig. 250. 



2 Ibid. p. 318 & fig. 306. 



