214 rAL.EONTOLOGY. 



of a Dikdhccplialus ; but, as there is no other form of py.ii-idiuiii hi the ruck 

 containing the heads, it Avould seem to bi3long with them. 



Formation and localiUj. — In hmestone of tlie Potsdam group, at luux-ka, 

 Nevada. Collected by Arnold Hague, esq. 



CKEPICEPHALrS (LOGANELLUS) GRANULOSUS D. Sp. 

 Plate II, figs. 2-3. 



Glabella and fixed cheeks when united having a quadrangular form, 

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

 p\ramidal form, with a bi'oadly-truncated summit. 



Glalx'lla short-conical, somewhat rapidly tapering in front of the 

 occii)ital fuiTow, and squarely truncate at the summit; height equal to the 

 width at the occipital furrow; surface depressed-convex, and marked l)y 

 tin-ee pairs of very oblique furrows, the posterior pair extending nearly 

 across and almost iniiting in the middle with the occipital furrow; 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 Avide as the center of the glal)ella, very 

 ])i-omiuent in the region of the eye, and rapidly declining anteriorly and 

 ])Osteriorly 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, rajiidly 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 eve to the anterior furrow of the glabella; occipital furrow 

 strongly marked on the lateral lind). 



Facial suture passing in a direct line from the ej-e to the anterior 

 margin, and from Ijehind the eve o))li(pU'ly backward to the posterior 

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

 occipital line. 



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

 tules. 



