NO. 22 CAMBRIAN TRILOBITES, 3D CONTRIBUTION RESSER 25 



Psalaspis patersoni (Hall) 



Conocephalites patersoni Haix, i6th Ann. Rep. New York State Cab. Nat. 



Hist, p. 159, pi. 7, figs. 45, 46, 1863. 

 Conaspis patersoni Hall, idem, p. 152. 

 Conaspis patersoni Walcott, Smithsonian Misc. Coll., vol. 57, no. 13, p. 358, 



1914. 



Upper Cambrian, Franconia; Trempealeau, and other localities, 

 Wisconsin; Reads Landing, Minnesota. 

 Cotypes.—AM.l<^.li. no. 328. 



PTYCHOPARELLA Poulsen, 1927 



Ptychoparella canadensis (Kobayashi) 



Chancia canadensis Kobayashi, Journ. Pal., vol. 10, no. 3, p. 164, pi. 21, 

 fig. 28, 1936. 



Middle Cambrian ; Cap Mountain Ridge, Mackenzie District, 

 Canada. 



Holotype. — Nat. Mus. Canada no. 8714. 



SAUKIELLA Ulrich and Resser, 1933 



Saukiella fallax (Walcott) 



Saukia fallax Walcott, Smithsonian Misc. Coll., vol. 57, no. 13, p. 378, pi. 

 67, figs. 2i-22a, 1914. 



Upper Cambrian, Wilberns ; (loc. 70a) 8 miles northu^est of Burnet, 

 Texas. 



Cotypes.—V.S.'NM. no. 58647. 



STIGMACEPHALUS, n. gen. 



In breaking up the Conaspis group, it is easy to remove the several 

 diverse forms. One of these, characterized below, lies between 

 Conaspis and the radically different genus Monocheilns. 



Diagnosis. — Rather small trilobites with large glabella. Glabella 

 occupies three-fourths the length of the head, tai^ered slightly, rounded 

 in front, and usually with pits in the anterior angles of the dorsal 

 furrows. Glabellar furrows practically absent. Brim convex and 

 turned downward, and with only a faint anterior furrow, which in- 

 volves no change in the slope of the brim. Fixigenes narrow ; eyes 

 small, situated about the middle of the head. Libragenes rather large, 

 evenly convex and with stout, long genal spines. 



Genotype. — Conocephalites oweni Hall. 



Name. — aTLjjxa — puncture ; Ke</>aAos = head. 



