NO. 5 UPPER CAMBRIAN TRILOBITES RESSER 93 



BERKEIA ANGUSTATA, new species 



Plate 15, Figures 34-39 



B. angnstata is a prolific species which appears to be narrower than 

 others from the same region. Its aspect is due to the relatively long 

 glabella and the angulation of the anterior margin. The glabella, 

 rounded in front, has two well-developed pairs of furrows. The neck 

 ring extends into a short blunt spine. In this species the preglabellar 

 area is considerably wider than the brim. 



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

 Mountains, Oklahoma. 



Holotype. — U.S.N.M. No. 108791a; paratypes, Nos. 108791b, c. 



BERKEIA SCULPTILIS, new species 



Plate 16, Figures 1-4 



This small species is not fully typical of the genus because of the 

 relative depression and constriction of the middle portion of its pre- 

 glabellar area. The prominent glabella stands well above the fixigenes. 

 It is rounded in front and has three pairs of furrows on exfoliated 

 specimens. The fixigenes average nearly half the glabellar width and 

 the brim width equals about one-third the glabellar length including 

 the neck ring. Both the anterior angles and the posterolateral limbs 

 are sharply downturned so that in dorsal view the strong curve of the 

 brim is exaggerated. The rim is thickened in the center, where it is 

 about as wide as the preglabellar area. 



Honey Creek limestone; (loc. 12k) Honey Creek, 7 miles north of 

 Springer, Wichita Mountains, Oklahoma. 



Holotype. — U.S.N.M. No. 108793a; paratype No. 108793b. 



BERKEIA JUCUNDA, new species 



Plate 16, Figures 5-10 



This is the smaller of the two species in the Davis formation. It 

 is typical of the genus in every respect, agreeing rather closely with 

 those Oklahoma species which are characterized by the wide pre- 

 glabellar area. The moderately convex glabella tapers at the normal 

 rate to a rounded front and has three pairs of furrows on exfoliated 

 specimens. The fixigenes are narrower than the brim, averaging about 

 one-third the glabellar width. The eyes are rather large, and the 

 palpebral lobe is angulated near its center. The brim width equals 

 half the glabellar length exclusive of the neck ring. It has a nearly 

 even brim about half as Vv^ide as the preglabellar area. The front 

 margin is slightly angulated in the middle. 

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