FOSSILS OF THE DEVONIAN. 



207 



PCECILOPODA. 

 Genus PHACOPS Emmerich. 



Phacops raua Green (Sp.). 

 Calymene bufo, var. rana Green, 1832. Monograph Trilobites North America, p. 42. 

 Phacops rana Hall, 1861. Desc. New Species of Fossils, etc., p. 65. Idem., 1862. Fif- 

 teenth Ann. Kep. N. Y. State Cab. Nat. His., p. 93. 

 Meek & Wortheu, 1868. Geol. Surv. 111., vol. iii, p. 447, pi. ii, figs. la-e. 

 Nicholson, 1873. Pal. Prov. Ontario, p. 123, fig. 5, 6 a. 

 Hall, 1876. Pal. N. Y., Illustrations of Devonian Fossils, Crustacea, pi. 



vii, figs. 1-11; pi. viii, figs. 1-17. 



Whitfiekl, 1883. Geol. Wisconsin, vol. iv, p. 330, pi. xxvii, figs. 17-19. 

 Compare Phacops bombifrons Hall. Pal. N. Y"., Illustrations Devonian Fossils, Crus- 

 tacea, pi. vi, figs. 18-29. 



A comparison of specimens from the Hamilton Group of New York 

 with those from Nevada shows variations that are quite strongly marked, 

 but which are scarcely of specific importance, if we consider that the east- 

 ern form is imbedded in a shale and more or less compressed, while the 

 Nevada examples are in a limestone, and have also undergone slight 

 changes resulting from the differences in their original habitat as compared 

 with the New York specimens. The glabella of the Nevada form is more 

 inflated and protruded in front, a narrow furrow occurs between it and the 

 eye, and the entire head is much more convex, but in one or two specimens 

 these characters are reduced and a typical head of Pliacops rana is shown. 

 The species as seen in most of the specimens resembles, in its prominent gla- 

 bella marked in the cast by the little elevations that filled the hollows of 

 the pustules seen in the outer surface of the dorsal shell, Phacops lombifrons, 

 and appears to be a species uniting the latter and Phacops rana. 



Formation and localities. Lower horizon of the Devonian limestone; 

 Comb's Peak and other localities in the Eureka District; also at Lone 

 Mountain, 18 miles northwest of Eureka, Nevada. 



Genus DALMANITES Emmerich. 13 



Dalmanites Meeki, n. sp. 



Plate xvii, figs. 5, 5a-c. 



Dalmanites (undt. sp.) Meek, 1877. Geol. Expl. Fortieth Parallel, vol. iv, p. 48, pi. i r 



figs. 11, 11 a. 

 The general form and the characters of the thorax are unknown, the 



