TRILOBITES. 73) 
Cyrtometopus scofieldi.] 
furrows are distinct, the first being the shortest, originating close to the frontal 
margin, the length of each being just about one-half the distance between their 
outer extremities measured in a straight line. The second furrows are longer, 
parallel for about one-half their length with the first pair, thence directed more 
strongly backward. The third furrows are again longer than the second, subparallel 
to them but deflected abruptly backward at their extremities where they are 
widened into a slight pit or excavation. The last do not reach the occipital furrow. 
» 
Figs. 53, 54.—Glabella of Psewdosphcerexochus trentonensis. 
The frontal lobe is relatively small and spherically subtriangular; the first pair 
of lateral lobes elongate rectangular, the second pair similar, though broader and 
- deflected somewhat posteriorly at both extremities, the third pair is short, clavate, 
one-half wider at its outer than at its inner extremity. The surface of the glabella 
is covered with low but distinct tubercles. 
Formation and locality.—Middle Trenton group, Trenton Falls, New York. 
Subgenus CYRTOMETOPUS, Angelin, 1854. 
CYRTOMETOPUS SCOFIELDI 1. Sp. 
This species is known only from its cranidium, of which a few examples are at 
hand. The part is small, having an axial length of about 64 mm., and a width 
between the extremities of the cheek spines of 16 mm. Glabella elongate-subquad- 
rate in outline, broadly rounded in front; dorsal furrows straight and subparallel; 
length to occipital groove equal to width at base. General contour depressed 
Vig. 55.—Cranidium of Cyrtometopus scofieldi. 
convex, flattened above. Frontal lobe large, first and second lobes small, obscurely 
defined, the former transversely subrectangular curving backward towards the 
dorsal furrows, the latter subtriangular and broadest within; third lobes moderately 
large, having a form just the reverse of that of the second lobes, and almost if not 
wholly set off from the glabella by the deep bounding furrows. The first and second 
