26 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 10^ 



tional structure between Drmnaspis on the one hand and Ehnnia on 

 the other. 



Genotype. — Charioeeplialiis (F) tiimifrons Walcott (not Hall and 

 Whitfield). 



PARAIRVINGELLA ANGUSTILIMBATA Kobayashi 



Plate 4, Figurks 18-22 



Chariocephaliis tuiiiifrons Walcott (not Hall and Whitfield), U. S. Geol. Siirv. 



Monogr. 8, p. 61, pi. 10, fig. 16, 1884. 

 Irz'iiigella (Parairvingclla) aiu/itstilimbatits Kobayashi, Jap. Journ. Geol. 



Geogr., vol. 15, Nos. 3-4, p. i/S, 1938- 



This species, represented by a number of cranidia, is recognized at 

 several localities. It is characterized by a wide glabella with furrows 

 of normal development. The glabella stands vi^ell above the fixigenes. 

 In cross section it is very steep at the sides but is flattened on top. 

 Longitudinally it has a marked convexity, most of which is in the 

 anterior half. The narrow brim consists of a clearly defined thickened 

 rim and a narrower preglabellar area. The slightly convex fixigenes 

 are almost exactly half the width of the glabella, and slope down 

 from the dorsal furrow. Posterolateral limbs depressed to a vertical 

 position. Anterior fixigenes also sharply depressed. The eyes are 

 long, extending forward almost to the anterior furrow, and are 

 angulated at about the midpoint. 



Secret Canyon shale; (Iocs. 62, 63) north of Adams Hill, Eureka 

 District, Nevada. 



Holotype and paralypcs. — U.S.N.M. No. 24643; plesiotypes, Xo. 

 108672. 



PARAIRVINGELLA EUREKENSIS, new species 



Plate 4, Figures 15-17 



The narrow glabella tapers a little in the anterior third to a rounded 

 front. The occipital and first pair of glabellar furrows are wide and 

 deep, and in the exfoliated holotype the other two pairs are visible. 

 Laterally the glabella is arched above the dorsal furrow. Longitu- 

 dinally it also has considerable convexity, most of which is attained 

 in the anterior fourth. The fixigenes are slightly more than half the 

 width of the glabella and, since the eyes are not greatly bowed, main- 

 tain their maximum width in the po.sterior two-thirds. Anteriorly the 

 fixigenes contract to about half their greatest width, and are con- 

 siderably depressed. The eyes are moderately long, and, because of 

 the wide anterior fixigenes, do not reach the line of the dorsal furrow. 



