OEISKAKT FAUNA OF BECKAFT MOUNTAIN 23 



vexity surrounding the glabella. The latter is ovoid, convex and large 

 extending two thirds the length of the cephalon. Its anterior extremity 

 is rather broad and blunt, and at its base are two subtriangular or ovoid 

 lobes set off from the glabella by deep, oblique furrows. The other 

 glabellar furrows manifest themselves in the manner characteristic of this 

 genus, the first pair making a broad indentation just in front of the 

 middle, very noticeable on the internal cast, and the second pair being 

 extremely obscure. The ornamentation of the head consists of very fine 

 pustules with larger ones scattered among them. This character is 

 maintained over the glabella to the frontal margin, where the coarser 

 pustules disappear, leaving the surface here with a very fine granulation, 

 and on the doublure this is replaced in part by punctation. 



Pygidium subcircular, axis very convex, incurving toward the 

 extremity. The annulations are narrow and not direct, but rise nearly 

 vertical from the dorsal furrows or with a slight forward inclination, 

 then, at less than one third of their length, bend forward with a dis- 

 tinct angulation curving anteriorly over the median line. These annula- 

 tions are nine, and beyond the last that is well defined may be counted 

 three more obscurely defined. The interannular grooves are narrow. 

 The pleurae are broad, convex about the median region, becoming 

 depressed toward the margin, sometimes defining a narrow border. The 

 ribs are seven, rather broad, obscurely grooved for most of their length 

 by a linear sulcus which becomes well marked on the border and gives 

 the ribs the appearance of being bifurcated. The intervening furrows 

 are narrow. The ornamentation consists of fine, uniform tubercles on all 

 annulations, with a single axial row of strong, spinous tubercles directed 

 posteriorly. 



This species, in its general aspect and comparatively large dimen- 

 sions, approaches Cord, cyclurus H. and C. of the Helderbergian 

 much more nearly than it does any of the later species, which are uni- 

 formly smaller and differently ornamented. In Cord, cyclurus the 

 cephalon has a few coarse tubercles on the border, and over the concave 

 area between the border and the glabella are fine, inosculating furrows. 

 The distance between the border and the anterior end of the glabella 

 is less in Cord, cyclurus than in Cord, becraftensis. In 



