NO. 22 CAMBRIAN TRILOBITES, 3D CONTRIBUTION — RESSER 27 



TRICREPICEPHALUS Kobayashi, 1936 



Tricrepicephalus yellowstonensis, n. sp. 

 Crepicephalus texanns Walcott (part), Smithsonan Misc. Coll., vol. 64, no. 3, 

 p. 209, pi. 30, figs. 4, 4a, 1 916. 



Compared with T. tripiinctatns, the similar species in the region, 

 T. yellozvstonensis clififers first in having fewer granules on the brim 

 and behind the eyes on the fixigenes, and practically none on the 

 glabella. A further very conspicuous difference is the evenness of rim 

 width due to lack of a forward projection in the middle. 



Upper Cambrian, Pilgrim; (loc. 151b) between Pebble and Soda 

 Butte Creeks, northeastern Yellowstone Park, Montana. 



Holotype and paratype. — U.S.N.M. no. 61523, 



Tricrepicephalus beltensis, n. sp. 

 Crepicephalus texanns Walcott (part), Smithspnian Misc. Coll., vol. 64, 

 no. 3, p. 209, pi. 29, fig. 7, 1916. 



In general appearance this species resembles T. yellowstonensis. It 

 differs in being less convex in both directions but more particularly in 

 the practically even distribution of granules over the entire cranidium. 



Upper Cambrian, Pilgrim; (loc. iSii) Smith River, 6 miles north- 

 east of White Sulphur Springs, Montana. 



Holotype.— v. S.N M. no. 61644. 



WHITFIELDINA, n. gen. 



This i^eculiar small trilobite is evidently rather rare, although one 

 hand specimen contains more than five cranidia. 



Diagnosis. — Glabella quadrate, about half the length of the head, 

 and extends back of the rear margin, without an occipital furrow, 

 the glabella itself tapering to the base of a long, slender spine. Brim 

 wide, with a wide convex preglabellar area and an upturned rim. Fixi- 

 genes nearly as wide as the glabella. Eyes small, situated about the 

 middle of the head. 



Genotype. — Conocephalitcs qiiadratus Whitfield. 



Whitfieldina quadrata (Whitfield) 



Conocephalitcs qiiadratus Wiiitfiei.I), Ann. Rep. for 1879, Wisconsin Gcol. 



Surv., p. 47, 1880; Geol. Wisconsin, vol. 4, p. 180, pi. i, figs. 15, 16, 1882. 

 Ptychoparia quadrangularis Vodges, California Acad. Sci. Occ. Papers, vol. 4, 



p. 353, 1893- 

 Ptychoparia ? quadrata Miller, N. A. Geol. p. 565, 1889. 



Upper Cambrian, Eau Claire, (Cedaria zone) ; Eau Claire and other 

 localities, Wisconsin. 



Cotypes. — Univ. Wisconsin. 



