No. 4.] BILLINGS — FOSSILS OF NEWFOUNDLAND. 475 



the length ; sides gently concave in the posterior two-thirds, and 

 slightly diverging from each other forwards ; anterior third and 

 front uniformly rounded. Neck segment with the margin con- 

 vex and projecting backwards, an obscure tubercle, or rather, an 

 ani2;ular elevation in the middle, neck furrows all across. There 

 are four glabellar furrows ; of these, the posterior is strongly 

 marked and extends in a nearly straight line all across; the 

 next two are linear, slightly impressed, extend inwards about 

 one- third the width of the glabella and are gently curved back- . 

 wards, but still almost at right angles to the sides. The anterior 

 furrow is short, extends inwards about one-fifth the width of the 

 glabella, and curves backwards at an angle of about 45*^ to the 

 sides. The dorsal furrow around the glabella is very shallow. 

 The fixed cheeks are triangular, nearly flat, with a small eleva- 

 tion, close to the extremity of the posterior furrow. Front of 

 the head with a moderately convex marginal rim, almotst in 

 contact with the glabella or separated therefrom by a narrow 

 space. The eye-lobe starts from a point close to the side of the 

 glabella and just opposite or a little behind the short frontal 

 furrow, and runs with a gently sigmoid curve (at first convex 

 outwardly, and then concave) backwards and outwards to the 

 posterior marginal furrow, which it reaches at a distance from 

 the sides of the glabella, about equal to the length of the neck 

 segment. The facial suture leaves the side of the glabella a 

 little in front of the anterior furrow, and runs outwards, nearly 

 at a right angle, but with a gentle convex curve, to the margin. 



The surface is covered with fine rippled striae. These on the 

 marginal rim are irregularly parallel with the margin ; on the 

 glabella they curve around the front, but further back, and on 

 the neck segment they have a rudely longitudinal direction, 

 curving outwards in crossing over the glabellar lobes. 



Length of the head of the largest specimen examined, 6 

 lines ; length of the glabella, including neck segment, 5 lines ; 

 width of glabella at the neck segment, 3 lines, at the front 

 pair of furrows, 3^ lines; width of the posterior margin of the 

 fixed cheek 3 lines ; length of the eye lobe, 4 lines. 



When compared with the species figured by Salter and Hicks 

 the following difi'erences become apparent: — A. I/enrici, Salter, 

 has the eye lobes with a gently uniform curve outwards. In 

 A. Salteri, Hicks, the eye lobes are also convex and the glabella 

 proportionally longer, while the neck furrow ^'is the only one 



