156 



Contributions to Palceontology. 



curving outwards 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 the 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 iii, fig. 25, and 

 Plate ii, fig. 43) is comparatively rare : neither do they seem relat- 

 ed by the strength and proportions of the parts ; for the glabella, 

 frontal limb and occipital spine are comparatively slender, while 

 the separated spines indicate a more robust animal. 



The glabella is known only in the greenish gray sandstone beds 

 at Miniska, 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 II, FIGS. 36-39; AND PLATE III, 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 occi- 

 pital furrow, rounded or slightly subtruncate in front. 

 Posterior furrow turning obliquely backwards ; middle 

 furrow less strongly marked ; anterior furrow still less 

 conspicuous, and in small specimens not distinguishable ; 

 occipital furrow shallow, well defined, and bending a 

 little forward towards its extremities ; occipital ring 

 flattened, having the same elevation as the glabella, 

 and of nearly equal width throughout. Dorsal furrow 

 shallow, defined, little depressed below 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. 



