DESCRIPTION OF A NEW TRILOBITE. 97 



front margin ; straight sides converging a little anteriorly, convex 

 towards the front ; depressed convex at the neck lobe ; neck fur- 

 row well defined, extending across, and directed obliquely for- 

 ward at each side — two oblique glabellar furrows at each side in 

 front of the latter, making an angle anteriorly of about 45° with 

 the axis ; the furrows are well marked interiorly but very obscure 

 at the sides, and are separated by about one half the width of 

 the glabella, forming three lateral lobes of nearly equal size, each 

 larger than the neck lobe. In some specimens there are three 

 glabellar furrows on each side, the front one making a greater 

 angle anteriorly with the axis than either of the others. 



Pleurae — twelve ; moderately convex outward from the axal 

 furrow, each marked by an equal deep groove to the tips, which 

 are of a horny aspect, recurved and extended into long spines ; 

 sides parallel as far back as the eighth segment, then gradually 

 ^converging to the pygidium. 



Axis — convex, gradually tapering to the extremity of the 

 tail, about two thirds of the width of the pleurae anteriorly — less 

 at the pygidium ; twelve body rings, and five or six caudal joints ; 

 the body rings notched above posteriorly and slightly swelled at 

 the axal furrows. 



Pygidium — entire ; semi-circular ; truncate behind ; lateral 

 lobes depressed convex, on a level with the pleuras ; four broad 

 ribs on each side of the middle lobe recurved towards the extremi- 

 ties ; margin smooth, and entire anterior angles moderately 

 bounded. 



Dimensions of largest specimen. 



Entire length 16 lines. 



Length of head 5 " 



" of thorax 8 " 



Axis of tail 3 » 



"Width at base of head 11 " 



" at eighth segment. 10 " 



" at front of pygidium 8 " 



" of axis at same place 1£ " 



Length of glabella 4 " 



Width at neck lobe 3£ " 



" at front of glabella 2\ " 



" between the eyes 4 u 



" of margin in front of glabella OJ " 



" ofborder 0J " 



'Can. Nat. 7 Vol. VIII. 



