October, 1913. New Trilobites — Slocom 73 



the longitudinal curve of the glabella is somewhat more abrupt in front, 

 making its anterior lobe appear shorter in dorsal view. This last 

 feature may be due to distortion. 



C. milleranus is 'distinguished from C. pleurcxanthemus by its propor- 

 tionally shorter cephalon, its less flaring genal spines, and by its eyes 

 being globular and situated about equidistant from the dorsal furrows 

 and from the posterior margin of the cephalon. The eyes of C. pleu- 

 rcxanthemus are conical and nearer the dorsal furrows. Further, the 

 spines of the pygidium in C. milleranus converge at their points instead 

 of diverging as in C. pleurexanthcmus. 



Locality and horizon. — Lower Maquokcta shales of Clermont and 

 Elgin, Iowa. 



Ce&ATOUS elginensis sp. now Plate XVII, Figs. 4-5. 



Type specimens Nos. P 16630A, 16630B, 17030 Field Museum. 



Cephalon sublunate, width more than three times the length, 

 anterior lateral margins arcuate, posterior margin transverse in the 

 median portion, gently bent backward near the genal angles. Glabella 

 convex, clavate, less than half the width of the cheeks at its posterior 

 margin but gradually widening anteriorly until its width nearly equals 

 its length ; anterior lobe constituting about one-fourth the entire length 

 of the glabella; three pairs of lateral furrows rather short, well defined, 

 defining three pairs of convex lateral lobes, diminishing in size poste- 

 riorly; the two anterior pairs of furrows are transverse, the posterior 

 pair are transverse for part of their length, then bent backward until they 

 join the occipital furrow, isolating the posterior lobes; occipital segment 

 elevated at the posterior margin, sloping into the occipital furrow; 

 occipital furrow shallow, concave in the median portion, narrower.- 

 deeper and bent backward behind the glabella lobes; dorsal furrows 

 deep, angular, forming deep angular pits where they merge into the 

 marginal furrows; cheeks large, convex, posterior angles produced into 

 long, stout spines, flattened anteriorly and pointing almost directly 

 backward; palpebral lobes elongated, large for the genus, placed well 

 forward, about midway between the dorsal furrows and the lateral 

 margins but nearer the posterior margins than the dorsal furrows. 

 Xcar the base of each lobe on the side towards the dorsal furrow is 

 situated a decided pit; an indistinct furrow extends from this pit to the 

 crest of the lobes ; the ocular ridges extend from the anterior angle of the 

 palpebral lobes to the pit in the dorsal furrows; the facial sutures 

 originate on the lateral margins about in line with the posterior mar- 

 ginal furrow, curve forward and inward to the palpebral lobes which 

 they traverse, then forward to the anterior margin, which they reach in 



