NO. 5 UPPER CAMBRIAN TRILOBITES RESSER 97 



about half the glabellar width. In front of the eye the suture diverges 

 little, but back of the eye it forms posterolateral limbs of normal shape. 



The brim, almost exactly a third of the cranidial length, has a 

 somewhat thickened rim considerably narrower than the preglabellar 

 area. Longitudinally the considerable convexity is attained by a sharp 

 bend about the midpoint. In cross section the relief is not so great, 

 as the nearly flat fixigenes slope less steeply, and the glabella is gently 

 arched. The anterior angles are not greatly depressed. The associated 

 pygidium is characterized by the usual large, stout axis standing well 

 above the pleural platforms and terminating very abruptly in the rear. 

 Deep pleural furrows rib the slightly convex pleural platforms. The 

 border turns up sharply all around. 



Honey Creek limestone; (loc. gq) Blue Creek Canyon, and other 

 localities in the Wichita Mountains, Oklahoma. 



i7o/o/3;/>^.— U.S.N. M. No. 108816a; paratypes, Nos. 108816b, c. 



ELVINIA LONGA, new species 

 Plate 18, Figures 24-27 



This species resembles E. grcgalis but must be regarded as distinct 

 owing to greater relative and absolute relief and its longer glabella. 



The long glabella appears to be slender. It tapers at a normal rate 

 to a rounded front margin. In spite of considerable relative relief 

 the glabellar furrows are very shallow. At the anterior end of the 

 eye the fixigenes are considerably more than half the glabellar width. 

 Their width is not greatly increased either forward or backward and 

 the posterolateral limbs are not so long. The brim occupies about 

 one-fourth the cranidial length, which makes it relatively narrower 

 than in A. gregalis. Both the rim and the preglabellar area are strongly 

 convex, the rim occupying a little more than a third the brim width. 

 Longitudinally the cranidium is decidedly convex, being slightly 

 curved in the rear half and sharply curved in the front portion. Since 

 the glabella and fixigenes are both convex, and the anterior angles 

 sharply depressed, the lateral convexity is great. 



Honey Creek limestone; (loc. 9p) Blue Creek Canyon, Wichita 

 Mountains, Oklahoma. 



Holotype. — U.S.N.M. No. 108817a; paratype. No. 108817b. 



ELVINIA BRIDGEI Resser 



Plate 18, Figures ^8-31 ; Plate 19, Figures 1-5 



Elvinia roemeri Bridge (part), U. S. Geol. Surv. Prof. Pap. 186-M, p. 251, 



pi. 69, figs. 19-21, 1937. 

 Elvinia bridgei Resser, Smithsonian Misc. Coll., vol. 97, No. 10, p. 31, 1938. 



