Ge7ius Aff7iostns. — Vogdex. 393 



anterior portion, with a transverse furrow just before it, separating 

 a narrow anterior portion; in some examples a faint transverse 

 furrow crosses back of the tubercle. Surface of the head and 

 pygidium finely granulose. 



Locality. Gallatin City, Montaaa, also in the Eureka District of Ne- 

 vada and elsewhere. 



Agnostus tumidosus Hall and Whitfield, 1877. Plate x, fig 8. 



Diagnosis. — Head highly dome-shaped in outline, slightly con- 

 tracted near the occipital border, very convex. Limb narrow, 

 flattened. Dorsal furrow distinct. Glabella small, less than f 

 as long as the head, conical and very convex, especiall}' tumid in 

 the lower part ; the central tubercle marked near its edge by a very 

 slight line which presents the appearance of a border surrounding 

 it. Frontal lobe about \ of the length of the glabella. Basal 

 lobes triangular and minute. Thorax unknown. The highl}^ 

 dome-shaped outline with the form and markings of the glabella 

 distinctly mark this species. 



Locality. Eureka, Nevada. The species is of the type A. quadratus 

 Tullberg. 



Agnostus interstrictus White, 1874. Plate x, fig. 6. 



Diagnosis. — This species of the type A. fallax Linrs. is ellip- 

 tical in form with a smooth surface. The head is broader than 

 long. Limb narrow, forming a narrow linear depression between 

 it and that portion of the head which it incloses. Glabella bilobed, 

 conical, well defined by the dorsal furrows, and sharply rounded 

 in front. A minute tubercle on the median line; near the poster- 

 ior end; the frontal lobe is marked off by a shallow transverse 

 furrow. Thorax of two joints, narrower than the head and 

 P3'gidium, giving the body the appearance of being constricted at 

 the middle. Axis broad, both its joints tumid at the ends, where 

 they reach the dorsal furrows; lateral lobes very narrow, pleurae 

 about as wide as long, each pleurae tumid and rounded at the ex- 

 tremities. Pygidium in form like the head. Axis a little longer 

 than the glabella, moderately convex, with a minute tubercle on 

 the median line near the anterior end. Sides between the mar- 

 ginal furrow and axis convex. The lateral angles of the pygid- 

 ium are produced into sharp spines. The basal lobes of the gla- 

 bella are very minute. 



Locality. Antelope Springs, Utah. 



