74 Annals of the Carnegie Museum. 



particular interest as it is the only representative of this genus as yet 

 definitely known from the American Ordovician. This specimen belongs 

 to a species very closely related to Ceratocephala coalescens van Ingen, a 

 species found in the Silurian limestone at St. Clair Spring, near Batesville, 

 Arkansas.^ The glabella here described differs from that of C. coalescens 

 in being slightly shorter and wider, and in having the surface covered with 

 minute granules instead of being smooth. 



Description. 



Cranidium, disregarding the spines, nearly circular in outline, slightly 

 and regularly convex, surface granulose. The second pair of glabellar 

 furrows turn backward parallel to the axis and divide it into three longi- 

 tudinal ridges, the central one large, expanding toward the front, and 

 reaching nearly to the anterior margin. The side lobes are small, reniform, 

 the third pair of furrows being represented only by pits, so that the second 

 and third lobes are coalescent. The fixed cheeks are small and convex, 

 the suture cutting close to the glabella. The neck-furrow is narrow and 

 deep, and the neck-ring wide. The ring bears two widely divergent spines 

 whose bases are separated. There are also two lateral pustules and a 

 median pustule on the upper surface of the ring. 



The cranidium, without the spines, is 1.5 mm. long, and the more 

 perfect spine is of about the same length. 



Locality. — The specimen is from McCullough's sugar-bush at Chazy, 

 New York, and is in the Carnegie Museum. The name is in honor of 

 Mr. J. E. Narraway, who has obtained many new and rare trilobites from 

 the vicinity of Ottawa. 



Genus Glaphurus Raymond. 



Glaphurus pustulatus (Walcott). 



Plate XVIII, figures 9-11. 



One of the specimens found by Professor Perkins on Isle La Motte is 

 the largest and finest ever obtained, and it is the only one now known which 

 retains the free cheeks in position. The course of the suture as shown 

 by this specimen indicates that the species belongs to the Acidaspidcz, 

 but the remainder of the animal is so different from other members of the 

 family that it seems best to elevate Glaphurus to generic rank, rather than 

 to consider it as a subgenus as was done in my previous paper. 



^School of Mines Quarterly, XXIII, 1901, 48, fig. 11. 



