44 PALEONTOLOGY OF THE EUEEKA DISTRICT. 



Occipital ring narrow, flattened; occipital furrow very shallow; fixed 

 cheeks narrow, separated from the glabella by distinctly marked dorsal 

 furrows, and sloping rapidly from the palpebral lobes before and behind; 

 palpebral lobes elongate, slightly sinuate, and with a groove within the 

 margin ; frontal limb broad, rather short, sloping down to a line or groove 

 beyond which the flattened margin extends, the width of the margin nearly 

 equaling the distance between it and the glabella; postero-lateral limits of 

 medium width, with the extension of the occipital furrow marking their 

 posterior portion ; their lateral extension is a little greater than one-half the 

 length of the head. 



Facial suture directed outward from in front of the eyelobe to the 

 anterior rim of the head, around which it abruptly curves, terminating at 

 the front margin; behind the eye it passes obliquely backward at an angle 

 of 25 with the posterior margin of the head, cutting the latter at a distance 

 from the dorsal furrow equal to the width of the anterior end of the glabella. 



Surface finely granulose under a strong magnifying glass. 



Thorax and pygidium unknown. One associated pygidium is much 

 like that illustrated by Hall and Whitfield, Geol. Expl. Fortieth Par., vol. 

 iv, pi. i, fig. 39. 



Formation and locality. Cambrian. Upper portion of Prospect Mount- 

 ain Group, near the Bullwhacker mine, Eureka District, Nevada. 



Dicellocephalus Marica, n. sp. 

 Plate x, fig. 13. 



Glabella and fixed cheeks subquadrate in outline, narrowing somewhat 

 towards the front. Glabella subquadrangular and almost squarely truncate 

 in front, which is not quite as wide as the base; strongly convex, and 

 marked by three pairs of furrows, the two anterior pair but slightly im- 

 pressed and very short; the posterior pair extend obliquely inward one- 

 third the distance across from each side, and are united by a slight trans- 

 verse furrow; occipital ring strong and elevated; occipital furrow well 

 defined; dorsal furrows strongly impressed; fixed cheeks moderately convex, 

 narrow in front, widening at the palpebral lobes, and sloping away rapidly 

 in front, and less so back of the eyelobes; eyelobes narrow, semicircular, 



