NO. 22 CAMBRIAN TRILOBITES, 3D CONTRIBUTION RESSER 3 



BERKEIA, n. gen. 



Diagnosis. — Small trilobites. Cranidium considerably arched. Gla- 

 bella over two-thirds length of the cranidium, slightly tapered, rounded 

 in front. Two pairs of glabellar furrows well impressed. Fixigenes 

 convex, less than half the width of glabella. Brim about as wide as 

 the fixigene, consists of convex preglabellar area and a narrower some- 

 what swollen rim. 



Pygidium also convex, with the axis extending to rear margin, and 

 with two well-marked furrows followed by faint ones. 



Genotype. — Agranlos convexus var. B. Berkey. 



Berkeia typica, n. sp. 



Agranlos cotwexns var. B. P.kkkk.y, Anicr. Geol., vol. 21, p. 2H8, pi. 20, figs. 

 S, 6, 1898. 



The generic description cites the features of the species. 

 Upper Cambrian, fronton; (loc. 82b) Taylors Falls, Minnesota. 

 Holotypes. — Columbia Univ. no. 22285. 



BLOUNTIA Walcott, 1916 



Blountia glabra (Walcott) 



Asaphiscus (Blainia) glabra Walcott, Smithsonian Misc. Coll., vol. 64, no. 5, 

 p. 394, pi. 63, figs, i-ie, 1916. 



Upper Cambrian, Nolichucky ; (loc. lO/x) Bull Run Knobs, 11 

 miles northwest of Knoxville, Tennessee. 

 Cotypes.—U.S.'N.M. nos. 62804-6. 



BOLASPIDELLA, n. gen. 



A small trilobite from the Middle Cambrian Wheeler shale fails 

 to fit any existing genus. It is represented by only a few cranidia 

 among the thousands of specimens collected from these beds. At first 

 glance it is like Bolaspis, particularly like B. errata which has only a 

 slight boss, but cannot be retained in the genus because the preglabellar 

 area is wholly depressed. 



Diagnosis. — Small trilobites with a roughly quadrangular cranidium. 

 Glabella small, extending about two-thirds the length of the cranidium, 

 arched. Glabellar furrows faint or lacking. Occipital ring heavy, 

 extending into a stout spine. Fixigenes wider than glabella, rising 

 from the dorsal furrow to the eyes. Eyes prominent, somewhat less 

 than median in size. Eye lines rather heavy, straight. Brim rather 

 wide, with a rolled rim and nearly flat preglabellar area. 



Genotype. — Ptychoparia fwusensis Walcott. 



