NO. 22 CAMBRIAN TRILOBITES, 3D CONTRIBUTION RESSER 7 



Fixigenes convex, rather wide, with a rim defined by a shallow 

 furrow. Genal spine sharp, sometimes as long as the cheek is wide, 

 and is directed straight out in line with the margin. 



Thoracic segments appear to have a strong furrow and considerable 

 backward bend at the fulcrum. Tips sharp and long. 



Pygidium short and transverse, tending to be triangular in outline. 

 Axis elevated above rather flat pleural lobes. Three or more axial 

 rings are well defined. Pleura fused, in some species sufficiently to 

 eliminate the separating furrows. Most or possibly all species carry 

 delicate marginal spines but in some species only the anterior segment 

 is thus developed. Rear margin sometimes indented medianly. 



G enotype .—ConocephaUtes perseus Hall. 



Conaspis perseus (Hall) 



ConocepliaUtes perseus Hall, i6th Ann. Rep. New York State Cab. Nat. 



Hist, p. 153, pl- 7, figs. 17-23 I pl- 8, fig. 33, 1863. 

 Conaspis perseus Hall, idem, p. 152; Walcott, Smithsonian Misc. Coll., vol. 

 57, no. 13, p. 357 (footnote), 1914. 



Upper Cambrian, Franconia; opposite the mouth of the Chippewa 

 River, Minnesota. Kickapoo and many other localities, Wisconsin. 

 Cotypes. — A.M.N.H. no. 319. 



COOSIA Walcott, 1913 



Coosia onusta (Whitfield) 



Crepicephaliis onustus Whitfield, Ann. Rep. Wisconsin Geol. Surv., p. -:^2„ 



1878 ; Geol. Wisconsin, vol. 4, p. 182, pl. i, figs. 22, 23, 1882. 

 Anomocarella onusta Walcott, Smithsonian Misc. Coll., vol. 64, no. 3, p. 204, 

 1916. 



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

 localities in Wisconsin. 



Holotype. — Univ. Wisconsin. 



Coosia connata (Walcott) 



Ptychoparia connata Walcott, Proc. U. S. Nat. Mus., vol. 13, p. 272, pi. 21, 

 fig. 2, 1890. 



Upper Cambrfan, Eau Claire (Crepiccphalus zone) ; (loc. 78a) 

 Eau Claire and other localities in Wisconsin. 

 Holotype.— U.S. I^M. no. 23855. 



Coosia wyomingensis, n. sp. 

 Batliyuriscus sp., Walcott, U. S. Geol. Surv. Mon. 32, p. 466, pl. 64, fig. 6, 

 1899. 



The pygidium on which this species is based is rather blunt, but 

 fully typical of the genus. Most of the surface is exfoliated and there- 



