8 SMITHSONIAN MISCELLANEOUS COLLECTION'S VOL. IO3 



Honey Creek limestone ; (loc. 27^) West Timbered Hills, Arbuckle 

 Mountains, Oklahoma. 

 Holotype.—U.S.'NM. No. 108634. 



CHARIOCEPHALUS AFFINIS, new species 



Plate i, Figures 14-20 



This species, represented by a number of examples of all parts, is 

 perhaps most closely allied to C. bulla. 



The glabella is well rounded at the anterior angles, but has parallel 

 sides and only two pairs of furrows. It is convex, having an even 

 curvature laterally, but longitudinally its greatest curvature is in the 

 anterior third. The nearly flat fixigenes, a little more than a third the 

 width of the glabella at their widest point, slant downward from the 

 shallow dorsal furrow at a smaller angle than the lateral slope of the 

 glabella. The eyes are long, extending forward beyond the lateral 

 dorsal furrow. An associated libragene and a pygidium are assigned 

 to this species. The pygidium is transverse and the axis does not rise 

 wholly above the pleural lobes. The pleural lobes form very narrow 

 platforms, which are elongate rather than triangular, and which slope 

 into a broad concave border with a thickened, slightly upturned rim. 



Honey Creek limestone; (loc. 37u) West Timbered Hills, Arbuckle 

 Mountains, Oklahoma. 



Cotypes.—U.S.NM. Nos. io8635a-c. 



CHARIOCEPHALUS AGRARIUS, new species 



Plate i, Figures 21-28 



In present collections this moderately large-eyed form is the most 

 common Charioccphalns species at the locality. It is represented by 

 all cranidial parts and the pygidium. 



The wide glabella expands only slightly, standing entirely above 

 the fixigenes. It is very convex laterally, with a slightly flattened 

 profile. Longitudinally it is also strongly convex, with the greatest 

 amount of curvature in the front half. The front outline is rounded, 

 and the dorsal furrow is relatively shallow. The brim is very slightly 

 thickened and is turned up to a nearly horizontal position. The fixi- 

 genes at their widest point are nearly half the width of the glabella. 

 The eyes extend from a short distance forward of the occipital furrow 

 to the dorsal furrow. Exfoliated specimens show normal depth for 

 glabellar furrows. The fixigenes are only slightly convex and slope 

 down from the rather broad and shallow dorsal furrow. Distinct pits 

 are developed at the anterior angles in the dorsal furrow. The libra- 



