42 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 93 



Upper Cambrian, Deadwood ; Castle Creek, Black Hills, South 

 Dakota. 



Cotypcs.—V.S.N.M. no. 24581. 



Modocia berkeyi, n. sp. 



Agraulos coiivcxus Berkey, Amer. Geologist, vol. 21, p. 288, pi. 20, figs. 9-1 1, 



pi. 21, figs. 3, 7, 1898. 

 Agraulos convcxus var. A. Berkey, idem, pi. 20, figs, i, 2, pi. 21, fig. 5. 

 Ptychoparia calymcnoides Berkey, idem, pi. 20, figs. 3, 4, pi. 21, fig. 4. 



It appears that variety A and the other specimens assigned to the 

 species are alike except for size. However, critical work will have to 

 be done to settle this point. Variety B of Berkey belongs to another 

 genus. 



Upper Cambrian, fronton ; Taylors Falls, Minnesota. 



Holotype. — Columbia Univ. no. 22283 ! paratypes, nos. 22286, 

 22307. 



Modocia glomerata (Walcott) 



Acroccphalitcs ? glomerattis Walcott, Smithsonian Misc. Coll., vol. 64, no. 3, 

 p. 179, pi. :^, figs. 7, 7a, 1916. 



This Specimen is typical of the genus Modocia, departing only in 

 the development of the median boss. 



Upper Cambrian, Deadwood ; (loc. 340c) near Rawlings, Wyoming. 

 Holotype. — U.S.N.M. no. 61 591. 



Moosia Walcott is a synonym of Elvinia Walcott (Smithsonian. Misc. 

 Coll., vol. 75, no. 3, p. 88, 1925). 



PLAGIURA, n. gen. 



Diagnosis. — Cranidium large, smooth, rather flat ; facial suture 

 converges slightly anterior to eyes ; behind the eyes it diverges rapidly, 

 forming wide, blunt posterolateral limbs. Brim about one-third as 

 wide as the glabella is long ; no rim separated. Fixed cheeks about 

 half width of glabella ; eyes small, situated opposite anterior third of 

 the glabella. Free cheeks simple curved bands, with rounded genal 

 angles. 



Pygidium triangular, broad, with anterior angles somewhat drawn 

 out ; axis wide, well separated by change in slope and extends nearly 

 to rear margin ; axial and pleural furrows present. 



Genotype. — Ptychoparia? cercops Walcott. ^ 



Range. — Upper Lower Cambrian, Canadian Rockies. 



Name. — rrAayto? = slanting ; ovpa = tail. 



