NO. 5 CAMBRIAN TRILOBITES RESSER 23 



No doubt the family is valid, but it must be confined to Dolichometopus 

 and Corynexochus, which occur only in the Atlantic Province ; hence 

 all other American and Asiatic forms must go into other genera. 

 Properly restricted, Dolichometopus contains the species D, acadicus 

 Matthew and D. sueciciis, the genotype. 



The following list shows the generic position of the North Ameri- 

 can forms not belonging to the Atlantic Province : 



D. baton = Anoria D. lodcnsis = Glossopleura 



D. bcssus ^= Anoria D. occidcntalis = Poliella 



D. bion = Glossopleura D. product us = Glossopleura 



D. boccar = Glossopleura D. tontoensis = Anoria 



D. expansus =^ (l>iot determined) D.varro :^ Housia 



The Oriental species ascribed to the genus all belong elsewhere. 

 Their revision is now under way. 



DUNDERBERGIA Walcott, 1924 



Dundcrbergia Walcott, Smithsonian Misc. Coll., vol. 75, no. 2, p. 56, 1924; 

 idem, no. 3, p. 85, 1925. 



Several species from Nevada, other than the genotype, D. nitida, 

 appear to belong to the genus. Undescribed species from other regions 

 also appear to belong to Dunderhergia. 



Genotype. — Crepicephalus (Loganellus) mtidits Hall and Whit- 

 field. 



Range. — Upper Cambrian beds representing the Pterocephalia zone. 



DESCRIBED SPECIES REFERRED TO DUNDERBERGIA 



Dunderhergia maculosa (Hall and Whitfield) 



Crepiceplialus (Loganellus) maciilosus Hall and Whitfield (part), U. S. Geol. 



Expl. 40th Parallel, vol. 4, p. 215, pi. 2, figs. 24, 25?, 1877. (Not fig. 



26 = D. halli.) 

 Ptychoparia maculosus Walcott, U. S. Geol. Surv. Monogr. 8, p. 269, 1884. 



Upper Cambrian, Secret Canyon; (loc. 62a) opposite Jackson Mine, 

 Eureka District, Nevada. 

 Holotype. — U.S.N.M. no. 90670. 



Dunderhergia halli, n. sp. 



Crepiceplialus {Loganellus) maculosus Hall and Whitfield (part), U. S. Geol. 

 Expl., 40th Parallel, vol. 4, p. 215, pi. 2, fig. 26, 1877. (See D. maculosa.) 



This figured pygidium is not froin the same locality as the head 

 of D. maculosa, and further, since the cranidia associated with this 

 tail are also distinct, the logical procedure is to combine the two as a 

 new species. 



