24 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. IO3 



rather tumid in the rear moiety. Laterally they first rise from the 

 broad dorsal furrow, then slope gradually to their outer margins. 



Secret Canyon shale; (loc. 60) near Richmond Mine, Eureka 

 District, Nevada. 



Holotype.— U.S.N. U. No. 108665. 



IRVINGELLA ADAMSENSIS, new species 

 Plate 4, Figures 7-11 



Like the other species at this locality, /. adaiiisciisis has a relatively 

 slender glabella and wide cranidium. It is represented by a number 

 of cranidia. 



The glabella is constricted toward the truncated front. The furrows 

 are developed about as usual, but a peculiar feature is found in the 

 slight depression in the sides of the ridge between the occipital and 

 first glabellar furrows. In cross section the glabella has a flattened 

 curvature, and longitudinally it curves with the cranidial convexity. 

 The rather wide and thickened brim is striated in the middle. The 

 fixigenes are about half the width of the glabella, a width they main- 

 tain with little change in the rear half, but in the anterior portion 

 gradually contract to the width of the brim. Laterally the fixigenes 

 are rather convex, rising from a fairly deep glabellar furrow. 



Secret Canyon shale; (loc. 60) near Richmond Mine, Eureka 

 District, Nevada. 



Holotype.— U.S. N.M. No. 108666a; paratype. No. 108666b. 



IRVINGELLA FLOHRI, new species 

 Plate 4, Figures 12-14 



This well-represented species is large compared to its associates. 



The glabella tapers forward to a rather straight front margin, and 

 the furrows are developed about as usual. Laterally the convexity of 

 the glabella is greatly reduced, though longitudinally it curves at an 

 even rate. The brim is of normal width, slightly rolled. The fixigenes 

 are about half the width of the glabella in their rear half, while the 

 anterior portion is very convex, overhanging the eyes at the anterior 

 angles. The eyes are very long, and the eye band is conspicuously 

 developed. 



The specific name is given in recognition of Dr. M. C. Flohr, who 

 was my assistant at the time when some of the fossils were collected. 



Secret Canyon shale; (loc. 60) near Richmond Mine, luireka 

 District, Nevada. 



Holotype.— U.S.N. M. No. 108667. 



