392 The American Geologist. jmie, 189^ 



Agnostus richmondensis Walcott, 1884. Plate ix, fig. 11. 

 Diagnosis. — Head moderately convex, length and breadth equal. 

 Glabella f the length and a little more than ^ as wide at the base 

 than the width of the head; elongate, conical in outline, 

 strongly defined by the dorsal furrows, with the anterior third 

 separated by a distinct transverse furrow ; a little less than mid- 

 way between this furrow and the posterior margin, a short furrow 

 penetrates from each side towards the base of a minute tubercle 

 situated on the median line. Basal lobes small, triangular. 

 Cheeks more convex than the glabella, separated in front of the 

 glabella by a furrow. Limb narrow. Surface ornamented by 

 slightly irregular depressed lines that indent the surface from the 

 margin nearly to the edge of the strong dorsal furrows. Surface 

 smooth under an ordinary magnifying power. 



Locality. Prospect mountain, Nevada. 



This species is identical with Agnostus americanus Billirgs. 



Agnostus maladensis Meek, 1873, aff. Agnosfas joseplia. 

 The author proposes this name for a species from Malade City, 

 Utah, which is closely allied to Agnostus joscplxi Hall, except that 

 the specimens do not exhibit the spines on the genal angles of the 

 head; the author remarks "none of which are in a condition 

 to remove all doubt on this point." 



Section LIMBATI. 

 Agnostus bidens Meek. Plate x, fig. 5. 

 Diagnosis. — Head moderately convex, slightly wider than long, 

 bordered by a rounded margin with a strongly defined marginal 

 groove. Glabella convex, narrow, more than | the length of the 

 head, converging anteriorly, sub-angular in front; two oblique 

 furrows posterior to the center enter from each side, and unite 

 just in advance of a small node, on the center of an elevation, de- 

 fined behind by a transverse furrow that bends backwards; be- 

 tween this furrow and the occipital furrow a narrow band extends, 

 widening out laterally, forming the basal lobes. Dorsal furrow 

 distinct. Cheeks convex and sloping rapidly to the marginal 

 groove from the somewhat elevated central portion. Thorax un- 

 known. The pygidium is armed with lateral spines, and is 

 strongly convex. Axis conical, extending more than f of the en- 

 tire length, ornamented with an elongated, angular tubercle on the 



