THE FAUNA OP THE ST. JOHN GROUP. 69 



on the axial line ; there is also a faint tubercular elevation on the middle of the anterior 

 lobe. The lateral lobes of the pygidium are somewhat narrowed in the middle of their 

 length, by the projecting sides of the axial lobe, and rapidly behind the pygidium, where 

 they connect. The dorsal furrow is deeply impresssed all around, and at the posterior 

 angle is very close to the marginal furrow ; this furrow is angled forward to the axial 

 lobe, and quadrately rounded at the posterior side of the pygidium. The lateral cusps are 

 broad and leaf-like, and the marginal fold behind them is constricted, and it is also nar- 

 rowed toward and at the anterior angles of the pygidium. 



The head of this little species is mvich like that of A. acutiloba (described hereafter) ; 

 and, if the pygidium above described does not belong here, pnrtUus may prove to be a 

 variety of that species. Of the Scandinavian species known to me, A. incertvs, Brogger, 

 comes nearest this species, but differs in the proportions of the parts. 



Length, 6J mm. ? Width, 3J mm. Dimensions of the head shield, 2 by 2| mm. 



Horizon and Locality. In the grey shales of Div. \.c, at Porter's Brook and Hanford 

 Brook, St. Martin's. Infrequent. 



Agnostus vir, n. sp. (Plate VII. Fig. 3.) 



Body elongate-elliptical, broader and quadrate behind. 



Cephalic shield elongate semi-elliptical, with straight sides, and angulated behind. 

 Dor.sal furrow distinctly impressed. Marginal fold and furrow rather flat and l>road. 

 Glabella subconical, obtuse in front, expanded behind ; the width at one third from the 

 base is about two fifths of that of the head shield, and the length about five sevenths of 

 that of the shield ; the anterior lobe of the glabella is about two fifths of its length ; it is 

 elliptically rounded in front, and obtusely rounded behind ; the posterior lobe is narrowed 

 behind, and in that part is decidedly elevated above the rest of the shield; a sigmoid 

 iurrow cuts off a depressed triangular basal lobe on each side of the glabella. The cheeks 

 are moderately raised, and are of nearly equal width all around the glabella. 



The thorax consists of two segments. The first segment is divided into three lobes, 

 of which the outer pair is globose ; the middle lobe is elongated transverse to the axis of 

 the thorax, and is indented on the front side by two strong furrows extending half way 

 across. The second segment of the thorax is similar to the first, except that there are no 

 furrows on the middle lobe. 



The pygidium is subquadrate, wider behind than in front, and bears a short cusp or 

 spine at each posterior angle ; its width is a fifth greater than its length. The axial lobe 

 is cyliudro-couical, obtusely pointed behind, and bears an elongated tubercle, pointed back- 

 ward ; at the anterior third it is about two fifths of the width of the pygidium, and it is 

 more than three quarters of its length. The lateral lobes of the pygidium are each about 

 half of the width of the axial lobe, and are narrowed toward the posterior end of the 

 pygidium, where they connect. The marginal furrow increases in width, going backward 

 as far as the posterior lateral angles, where it is as wide as the lateral lobe, but narrows 

 again toward the extremity of the pygidium ; the marginal fold increases in width from 

 the front as far as the lateral cusps, behind which it is constricted ; at the forward end it 

 is angulated toward the axial lobe, and in the posterior third is broadly rounded. 



The cephalic shield in this species is quite like that of il. Acadictts, Hartt, but presents 



