242 TAL^^ONTOLOGY. 



recurving to the eye, leaving the limb nearly two-thirds as wide at its 

 widest point as the glabella. 



This species differs from any other described in the length of the 

 glabella and the position of the fun-ows, in the short frontal limb, and great 

 lateral extension of the same. No other parts of the species have been 

 recognized. There are, however, several specimens of a pygidium associ- 

 ated in the same slates, and, as they are the only remains of Trilobites 

 occurring in the slates, except C. (L.) qitadrans, which cannot well be con- 

 founded with either, it would be natural to suppose they were parts of the 

 same species. But the characters of the pygidium are so unlike anything 

 heretofore recognized or known to belong to the genus DikellocepJiahis, that 

 we have great doubt of their generic identit}', and for that reason have 

 placed them under different specific names with a doubt as to the generic 

 reference. 



Formation and localitij. — In green argillaceous slates of the Quebec 

 group, in the cafion above Call's Fort, Wahsatch Eange, Utah. Collected 

 by S. F. Emmons, esq. 



DiKELLOCEPHALUS ? GOTHICUS n. Sp. 

 Plate I, fig. 36. 



Pygidium semi-ovate, or short paraboloid, Avitli a very strong central 

 axis, and spinose margin ; anterior margin straightened for about two-thirds 

 the width of the lateral lobes, where it curves abruptly backward to the 

 lateral angles. Axial lobe strong, cylindrical, and prominent, forming one- 

 third of the entire width exclusive of the spines, and reaching almost to the 

 posterior margin of the shield ; obtusely rounded at the extremity, and 

 marked by six annulations exclusive of the terminal ones. Lateral lobes 

 very moderately convex, and marked by foin- divided ribs on each side, 

 each terminating in a strong and proportionally long marginal spine ; central 

 area of each rib depressed, forming a flattened groove, extending to the base 

 of the marginal spine. Borders of the ribs elevated, the anterior one 

 strongest and prominent, gradually widening from its origin to the margin 

 of tlie .shield ; posterior border narrow and rounded, separated from the next 

 succeeding rib by a sharply-depressed, narrow groove. This peculiar form 



