NO. 10 CAMBRIAN FOSSILS, 4TII CONTRIBUTION RESSER 4I 



characterized particularly by well-developed anastomosing lines on the 

 glabella and libragenes. 



Upper Cambrian, Davis; (loc. lie) southwest of Potosi, Missouri. 



Holotypc— U.S.N. M. no. 93018. 



Pterocephalia ulrichi, n. sp. 



Ptcroccphalia sanctisahae Bridge (part), U. S. Geol. Surv. Prof. Pap. \^G-M, 

 p. 246, pi. 68, figs. 19, 21, 1937. 



This is a large, wide species with a wide flaring brim. In fact, 

 this is the widest species thus far found. The glabella is wide and 

 rounded in front. Likewise the anterior margin of the cranidium is 

 more rounded than in most species. The dorsal furrow is both wide 

 and deep, so that the glabella and cheeks next to it have considerable 

 relief. 



The pygidium is rather wide, the border of moderate width and 

 the rear margin evidently not notched. 



Upper Cambrian, Honey Creek; (loc. 9q) 15 miles northwest of 

 Fort Sill, and (loc. 91L') northeast of Big Baldy, Wichita Moun- 

 tains, Oklahoma. 



Holotypc. — U.S.N.M. no. 93016; paratype, no. 93014. 



Pterocephalia silvestris, n. sp. 

 Pterocephalia sanctisahae Bridge (part), U. S. Geol. Surv. Prof. Pap. 186-M, 

 p. 246, pi. 68, fig. 20, 1937. 



This is also a wide form and has a very large brim. Compared 

 with P. ulrichi, the brim is longer and the dorsal and glabellar furrows 

 shallower. 



Upper Cambrian, Honey Creek; (loc. 91a) 4 miles southeast of 

 Hennepin, West Timbered Hills, Arbuckle Mountains, Oklahoma. 



Holotypc— U.S.N.M. no. 93015. 



Pterocephalia deckeri, n. sp. 



Pterocephalia sanctisahae Bridge (part), U. S. Geol. Surv. Prof. Pap. 186-M, 

 p. 246, pi. 68, figs. 22, 31, 1937. 



This species is particularly wide opposite the front end of the gla- 

 .bella. The eyelines are heavy and the eyes prominent by reason of 

 their upturned position, but the palpebral lobes slope up only moder- 

 ately. The surface is highly ornamented in the usual fashion, but the 

 anastomosing lines on the glabella and fixigenes have such a fine mesh 

 that the surface appears to be granulated. 



The pygidium is rather narrow and high. 



