94 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. IO3 



Davis formation; (loc. iik) Federal Lead Mine No. 4, Flat River, 

 Missouri. 



Holotypc. — U.S.N.M. No. 108794a; paratypes, Nos. 108794b, c. 



BERKEIA MISSOURIENSIS, new species 



Plate 16, Figures 11-14 



This abundant species associated with Pterocephalia and Burnetia 

 is one of the largest found. The slightly truncate glabella has three 

 pairs of furrows. The very narrow fixigenes at the anterior end of 

 the eye are only about one-fourth as wide as the glabella. On the 

 other hand the brim is wide, equaling more than a third the glabellar 

 length. In this species the eye lobes are only slightly curved. A small 

 node occurs on the neck ring. 



Davis formation; (loc. iik) Federal Lead Mine No. 4, Flat River, 

 Missouri. 



Holotype. — U.S.N.M. No. 108795a; paratypes, Nos. 108795b, c. 



UNCLASSIFIED GENERA 



ELVINIA Walcott, 1924 



ELVINIA MONTIS, new species 



Plate 18, Figures 1-4 



E. inontis is characterized bya normally tapered, truncate glabella. 

 Two pairs of furrows are present, the rear pair taking a straight 

 course in the middle third. The brim width is about half the length 

 of the glabella exclusive of the occipital ring. It has a narrow rim, 

 which at its widest point equals about half the preglabellar area. At 

 the front end of the eye the fixigenes are half the glabellar width. 

 Back of the rather strongly bowed eyes, which slope outward at an 

 angle somewhat greater than the course of the dorsal furrow, the 

 fixigenes expand into wide posterolateral limbs. On the outer surface 

 none of the furrows are deeply impressed, and the surface apparently 

 is smooth. 



It was hoped that this form would turn out to be E. tctoncnsis, the 

 species previously known from western Wyoming. Unfortunately it 

 proved impossible to place it in that species owing to the more truncate 

 glabella, less evenly curved glabellar furrows, and more strongly 

 bowed eyes. 



Snowy Range formation; (loc. 37r) Warm Spring Creek, Wind 

 River Range, Wyoming. 



Holotype.— {J. S.'NM. No. 108812a ; paratype, No. 108812b. 



