NO. 4 CAMBRIAN TRILOBITES, 2D CONTRIBUTION RESSER 21 



out from the anterior portion of the glabella or rather the dorsal 

 furrow. 



Occurrence same as preceding. 



Halo type. — Presumably R. O. M. 



Ctenocephalus granulatus (Walcott) 



Conocoryphe (Subgenus?) matthewi granulata Walcott, U. S. Geol. Surv. 



Bull. lo, p. 30, pi. 4, fig. lb, 1884. 

 Conocoryphe elegans Walcott (part), idem, pi. 4, fig. 2a. 



Occurrence same as preceding. 

 Holotype. Cornell Univ. 



HOLOCEPHALINA Salter, 1864 



Holocephalina Salter, Quart. Journ. Geol. Soc. London, vol. 20, p. 21,7, 1864. 



HolocephaUna Illing, idem, vol. 71, p. 424, 1915. 



Lioceplmlus Gronwall, Danmarks Geol. Unders., vol. 2, no. 13, pp. 84, 213, 1902. 



Gronwall designated Conocoryphe imprcssa Linnarsson as the geno- 

 type of his subgenus Liocephalus. This species, together with C. lyelli, 

 belongs to Bailiella, which fact alone would invalidate Liocephalus. 

 However, it seems that Gronwall's concept of Liocephalus was that of 

 Salter's Holocephalina, which, being the earlier name, must be the 

 recognized genus. Moreover, Gronwall described a good species of 

 Holocephalina 3,s L. linnarssoni. 



Diagnosis. — A rather small trilobite with convex cephalon. Gla- 

 bella distinctly marked by shallow dorsal furrow. Marginal furrow 

 also shallow ; thorax and pygidium typical of the family. 



Comparisons. — Holocephalina needs only to be compared with 

 Hartshillia and the new genus Dasometopus. Illing has already dis- 

 tinguished the first two, and the features of the last named are pre- 

 sented with its discussion. 



Genotype. — H. primordialis Salter. 



Range. — Same as Conocoryphe. 



Three species have been recognized previously in the genus, H. pri- 

 mordialis, H. holocephala Miquel, and //. incerta Illing. 



Holocephalina linnarssoni (Gronwall) 



Conocoryphe (Liocephalus) linnarssoni Gronwall, Danmarks Geol. Unders., 

 vol. 2, no. 13, pp. 102, 214, pi. 2, fig. I, 1902. 



Middle Cambrian, Exsulans limestone ; Borregaard, Bornholm, 

 Denmark. 



Holotype. — Min. Mus. Copenhagen. 



