214 rAL^OiflOLOGY. 



of a Dihellocephalus ; but, as there is no other form of pygidium in the rock 

 containing the heads, it would seem to belong with them. 



Formation and locality. — In limestone of the Potsdam group, at Eureka, 

 Nevada. Collected by Arnold Hague, esq. 



'I ; Crepicephalus (Loganellus) granulosus n, sp. 



Plate II, figs. 2-3. 



Glabella and fixed cheeks when united having a quadrangular form, 

 with projecting posterior lateral limbs, giving to the whole a somewhat 

 pyramidal form, with a broadly-truncated summit. 



Glabella short-conical, somewhat rapidly tapering in front of the 

 occipital furrow, and squarely truncate at the summit; height equal to the 

 width at the occipital furrow; surface depressed-convex, and marked by 

 three pairs of very oblique furrows, the posterior pair extending nearly 

 across and almost uniting in the middle with the occipital fuiTow; anterior 

 pair very short and faint, situated near the anterior angles of the glabella; 

 second pair intermediate in size and position. 



Fixed cheeks about half as wide as the center of the glabella, very 

 prominent in the region of the eye, and rapidly declining anteriorly and 

 posteriorly from this point; palpebral lobes long and narrow, rather distinct 

 and prominent. Frontal limb nearly half as long as the glabella anterior 

 to the occipital furrow, rapidly declining forward, and bordered by a 

 thickened rounded rim, which is equal to one third of the entire length of 

 the limb; the space between the glabella and the marginal rim is strongly 

 convex. Posterior lateral limbs triangular, once and a half as long as high ; 

 ocular ridges existing in the form of an abrupt elevation, passing from the 

 front of the eye to the anterior furrow of the glabella; occipital furrow 

 •strongly marked on the lateral limb. 



Facial suture passing in a direct line from the eye to the anterior 

 margin, and from behind the eye obliquely backward to the posterior 

 margin of the head, forming an angle of about thirty degrees to the 

 occipital line. 



Surface of the crust densely covered by rather coarse granules or pus- 

 tules. 



