I 



NO. 5 UPPER CAMBRIAN TRILOBITES RESSER IO5 



is about average in size and shape and has the usual three sets of 

 furrows. The brim width is half of the glabellar length exclusive of 

 the neck ring. Fixigenes are rather narrow, averaging a little more 

 than a third of the glabellar width. Surface finely granulose. 



Wilberns formation; (loc. 68) Packsaddle Mountain, ii miles 

 southeast of Llano; and (loc. 70) Baldy Mountain, 8 miles northwest 

 of Burnet, Texas. 



Holofype.— v. S.N M. No. 108836a; paratypes, Nos. io8836b-d. 



TAENICEPHALUS WICHITAENSIS, new species 

 Plate 21, Figures 13-17 



A number of cranidia occur in a coarsely granular limestone full 

 of trilobite fragments. Much of the rock is nearly white, but it 

 contains many particles of glauconite and most of the trilobites are 

 stained red, which gives the rock a peculiar appearance. This species 

 is normal in all respects. The fairly wide glabella is truncated in the 

 front. All specimens are exfoliated, and on them three sets of furrows 

 are visible. The neck ring expands, possibly bearing a short spine. 

 The brim width exceeds the length of the glabella including the neck 

 ring. It consists of a rim that expands rapidly forward in the middle 

 from a nearly straight anterior furrow to give the front of the head 

 a considerable projection. The rim shrinks to extinction at the 

 anterior angles from the same width as the preglabellar area at the 

 center while the latter maintains its width into the anterior angles. At 

 the front end of the eye the fixigenes are less than half the glabellar 

 width, an average which they maintain throughout. The fairly large 

 eyes are in normal position for the genus. Triangular posterolateral 

 limbs are of considerable size. Surface of available exfoliated speci- 

 mens smooth, as are the small fragments of test remaining. 



Honey Creek limestone; (loc. Qq) Blue Creek Canyon, 15 miles 

 northwest of Fort Sill, Wichita Mountains, Oklahoma. 



Holotype. — U.S.N.M. No. 108837a; paratypes, Nos. io8837b-d. 



TAENICEPHALUS QUINNENSIS, new species 



Plate 21, Figures 18-23 



This species is represented by cranidia, libragenes. and a pygidium. 

 Owing to greater width across the anterior part of the cranidium and 

 the flatter relief in the brim, the species approaches Elvinia in 

 appearance. 



The fairly wide glabella, well rounded in front, has the usual sets 

 of well-defined furrows, tlie rear pair being connected across the 



