CONTRIBUTIONS TO PALiEONTOLOGY. ' 167 



upper side, or evidence of infolding of the crust on the lower side ; but the 

 thickened parts near the base are rounded above, slightly flattened below, 

 and longitudinally striated, with that extremity sharply truncated as if by 

 a suture. In the specimen fig. 5 there is, on what maybe the posterior side, 

 a narrow thickened border not unlike a cheek-border, with the impression 

 of a th!n expanded crust resembling a cheek-shield irregularly broken off 

 along the inner margin. 



We might suggest that the spine, like fig. 5, proceeded from the middle 

 or anterior part of the movable cheek, near the facial suture, curving out- 

 wards and backwards ; and that the expanded crust within the thickened 

 curving border below (which is broken on its inner margin) is a part of the 

 cheek-shield near the posterior angle. 



Although Dr. Owen has referred these spines to tho same species with 

 the glabella which he denominated Lonchocephalus hamulus, I have no 

 evidence of such relation of the two fossils. While the spines are extremely 

 numerous, the glabella ( Plate viii, fig. 25, and Plate vii, fig. 43) is compa- 

 ratively rare : neither do they seem related by the strength and proportions 

 of the parts ; for the glabella, frontal limb and occipital spine are compa- 

 ratively slender, while the separated spines indicate a more robust animal. 



The glabella is known only in the greenish gray sandstone beds at Mi- 

 niska, where it is associated with the spines as described by Dr. Owen. 

 Spines of the same character occur in the greenish and compact ferruginous 

 sandstones at Trempaleau, much more numerously than at Miniska ; but 

 the glabella has not been found in the same association. 



CONOCEPHALITES DIADEMATUS ( n.s.). 



PLATE VII, FIGS. 36 - 39; AND PLATE VIII, FIGS. 18 & 21? 



Head broad, moderately convex, with widely extended cheeks and 

 frontal limb. 



Glabella prominently convex, subovate-conical, about five-sixths 

 as wide at base as its length from the occipital furrow, rounded 

 or slightly subtruncate in front. Posterior furrow turning ob- 

 liquely backwards ; middle furrow less strongly marked ; ante- 

 rior furrow still less conspicuous, and in small specimens not 

 distinguishable ] occipital furrow shallow^, w^ell defined, and 

 bending a little forward toward its extremities : occipital ring 

 flattened, having the same elevation as the glabella, and of 

 nearly equal width throughout. Dorsal furrow shallow, defined, 

 little depressed beloAV the plane of the fixed cheeks, which are 

 flattened and much below the convexity of the glabella : the 

 furrow is continued, though less strongly defined, in front of the 

 glabella. 



Fixed cheeks flat, half as wide as the glabella. In the larger spe- 



