38 PALEONTOLOGY OF NEW YORK. 



groove upon the surface. Bonier narrow at the sides, produced at the 

 postero-lateral angles into two broad, stout, incurving cornua, whose inner 

 bases are continuous and form an elevated marginal collar at the posterior 

 extremity. The articulating ring and each pleural annulation, at its termina- 

 tion upon the margin, bears a round, smooth terete, and gently incurved 

 spine These spines are shortest in front and increase in length toward the 

 posterior cornua. The posterior collar has a width equal to that of the axis 

 on its anterior margin, ami hears a series of strong spines; one situated 

 centrally, bifurcating at two-thirds its length, and, in a large individual, 

 reaching a height of 10 mm., a short accessory pair of spines near the base of 

 the foregoing (sometimes absent), a second ami stronger pair at the beginning 

 of the posterior curve, a third pair at the base of the broad terminal spines, 

 and the incurved, elevated terminal spines or cornua, each of which bears an 

 accessory spine near the apex. (See plate xv, figs. 1-3.) The height of the 

 cornua in a large example is 12 mm. 



The Surface of the pygidium is covered with strong, sub-spiniform, irregu- 

 larly disposed nodes. Upon the axis each annulation bears but a single row, 

 but no arrangement in longitudinal rows is discernible. Upon the pleurae 

 there is evidence of an irregular, double row of nodes, but at the lateral and 

 posterior margins the nodes are more abundant and irregularly disposed. 

 A single example having an irregularly nodose axis, and a central spine on 

 the posterior collar, has the pleural nodes relatively small, abundant and 

 arranged in two regular rows as in Dalmanites aspectans, affording evidence of 

 the affinity of these two species in this respect. The characteristic orna- 

 mentation of Dalmanites myrmecophorus is however exhibited in pygidia 

 varying widely in dimensions, the smallest individual noticed retaining this 

 feature quite as strongly marked as the largest. 



A single large glabella which differs from that of any known species of 



the Upper Ilelderberg group, may belong to this species. It has the general 



outline and contour of the glabella in typical Dalmanites, except that there 



• an apparent tendency to obsolescence in the second lateral furrows. The 



frontal lobe hears a pair of conspicuous nodes just behind its center, and a 



