Genus Agtiostus. — Vogdes. 391 



author states that there is no fissure extending from the glabella 

 to the anterior margin. The absence of this groove ma}- be due to 

 the state of preservation. This species agrees in every other re- 

 spect with A. neon. Agnostus neon differs from A. commuma in 

 minute points, especially in the absence of the tubercle on the 

 glabella. 



Agnostus orion Billings, 1860 (cf. A. jnsiformis Linne). 

 Plate IX, fig. 12. 



Diiignosia. — Length and breadth about equal, sub-circular, con- 

 vex, a very narrow margin all around. Glabella not quite f the 

 whole length, very convex; a transverse furrow at one-third the 

 length from the apex ; small triangular basal lobes without a median 

 tubercle. Cheeks divided in front of the glabella by a furrow. 



Locality. Point Levis, Quebec. 



The same term was used by Barrande in 1846 for a species of this 

 genus. If this species differs from A. pisiformisii is only in the absence 

 of the median tubercle, which may be due to its state of preservation. 

 There is a slight indication of the tubercle on one of my cabinet speci- 

 mens from Point Levis. A pygidium from the same locality is similar 

 to that of Agnostus insiformis. 



Agnostus josepha Hall, 1863. Plate ix, fig. 17. 



Diagnosis. — Head semi-elliptical, margined by a flattened or 

 concave narrow limb; genal angles produced into short spines. 

 Glabella prominent, narrow, extending about f the length of the 

 head, and crossed by a shallow furrow near the anterior end. The 

 posterior lobe is marked by an oblique furrow on each side; a 

 small node on the summit at the anterior termination. The trian- 

 gular space on each side between the transverse and oblique fur- 

 rows is like- wise elevated into a low node. The posterior central 

 portion is gibbous. The ba?al lobes small and triangular in form. 

 Cheeks divided in front of the glabella b)^ a furrow. Pygidium 

 of the same form as the head. Axis prominent, subquadrate, 

 wider than long, nearly ^ the length of the pygidium, bearing a 

 node or short spine on its posterior extremity ; sides and body of 

 the pygidium, outside of the axis, highly convex. 



Locality. Trempealeau and elsewhere on the Mississippi about lake 

 Pepin, Wisconsin. The species occurs with Anomocare wisconsensis and 

 Ptychaspis granulosa. 



