l8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 95 



divergent species. The second, unquestionably a valid generic differ- 

 ence, is the manner in which the brim is divided. In Wilbernia the 

 rim. usually occupies fully two-thirds of the brim, whereas in Lito- 

 cephalus it is always less than half the brim width. Litocephalus has 

 vertical striations across the preglabellar area and the anterior outline 

 is straighter. 



Genotype. — Dicellocephaliis richmondensis Walcott. 



Natne.- — Atros = simple ; K6<^aAos'=head. 



Litocephalus richmondensis (Walcott) 



Dicellocephaliis richmondeivsis Walcott, U. S. Geol. Surv. Mon. 8, p. 441, 



pi. 10, fig. 7, 1884. 

 Ptychoparia richmondensis Walcott, Smithsonian Misc. Coll., vol. 57, no. 13, 



p. 352, 1 91 4. 



Upper Cambrian, Secret Canyon; (loc. 60) opposite the Richmond 

 mine, and (loc. 61) south of the Hamburg Mine, Eureka District, 

 Nevada. 



Holotype.—lJ.S.l<l.M. no. 24616. 



Litocephalus walcotti, n. sp. 



Ptychoparia anytus Walcott (not Hall and Whitfield), U. S. Geol. Surv. 

 Mon. 8, p. 56, pi. 9, fig. 26, 1884. 



Walcott identified a small cranidium with Hall and Whitfield's 

 species, but besides its smaller size it has a narrower preglabellar area. 

 Its features seem to require its reference to Litocephalus. Compared 

 with L. richmondensis it has narrower fixigenes. 



Upper Cambrian, Secret Canyon; (loc. 63) northeast of Adams 

 Hill, Eureka District, Nevada. 



Holotype. — U.S.N.M. no. 24656. 



LONCHOCEPHALUS Owen, 1852 



Lonchocephalus tipperaryensis (Miller) 



Marjumia ? tipperaryensis Mii-LER, Journ. Pal., vol. 10, no. i, p. 2)3, pl- 8, 

 figs. IS, 16, 1936. 



Upper Cambrian ; Crow Creek canyon, 3 miles north of Tipperary, 

 Owl Creek Range, Wyoming, 



Holotype. — Columbia Univ. no. 12606. 



Lonchocephalus winona (Hall) 



Conocephalites winona Hall, i6th Ann. Rep. New York State Cab. Nat. 



Hist., p. 161, pl. 7, figs. 26-28, 1863. 

 Anomocarella ? winona Walcott, Smithsonian Misc. Coll., vol. 57, no. 13, 



p. 358, 1914. 



Upper Cambrian, Eau Claire ; opposite mouth of Black River, and 

 (loc. 84) Dresbach, Minnesota. 

 Cotypes.—A.M.l<i.U. 



