82 Field Museum of Natural History — Geology, Vol. IV. 



the posterior forks bending abruptly backward and joining the occipital 

 furrow leaving the small posterior lobes entirely detached; the anterior 

 and larger forks bending obliquely forward denning the third glabella 

 lobes; occipital segment wide, slightly rounded, of about uniform width 

 until near the dorsal furrows where it is abruptly constricted; occipital 

 furrow shallow but distinct. Dorsal furrows narrow and deep, nearly 

 parallel from the posterior margin of the cephalon to the posterior 

 glabella furrows, thence diverging in a regular curve to the anterior 

 angle of the eyes where they become obsolete. Palpebral lobes large, 

 prominent, exceeding the glabella in height, marked with a distinct 

 furrow just within and parallel to the border of the eye; eyes large, 

 lunate, extending from the posterior cheek furrows to the anterior fur- 

 rows of the glabella; eye facets arranged in vertical rows of eight facets 

 each; the cheeks curve regularly to the lateral margins, marginal bor- 

 ders rather wide on their lateral margins, narrow on their posterior 

 margins, marginal furrows shallow on their lateral margins, narrower and 

 deeper on the posterior margins. The facial sutures originate on the 

 lateral margins well in front of the genal angles, curve inward and 

 backward to the posterior angles of the eyes, follow the inner margin of 

 the eyes to their anterior angles and thence curve outward to the 

 margin of the cephalon, almost in line with the anterior furrows of the 

 glabella. Surface of the glabella distinctly pustulose; that of the 

 palpebral lobes, cheeks, occipital ring and anterior projection finely 

 granulose. 



Thorax not known. 



Pygidium subtriangular, somewhat rounded posteriorly, distinctly 

 trilobed. Axis narrow, convex, margin slightly incurved, abruptly 

 rounded posteriorly; there are thirteen sinuous annulations; the dorsal 

 furrows entirely surround the axis; the pleural lobes, marked by seven or 

 eight segments each bearing a median groove for part of its length, curve 

 regularly to the lateral margins ; both segmentation and grooves become 

 obsolete a short distance from the margin, leaving a plain, undefined 

 marginal border. The entire surface of the pygidium is finely punctate. 



Measurements. — Type specimen (Mus. No. P 11256). Length of 

 cephalon on median line 9.5 mm., length including genal angles 10 mm., 

 width of cephalon 14.5 mm.; length of pygidium 9.2 mm., width 10.6 

 mm., width of axis on anterior margin of pygidium 3 mm., length of axis 

 7 mm. Another complete cephalon gave the following: Length on 

 median line 11 mm., length including genal angles 12.5 mm., width 

 17.5 mm. 



Remarks. — The above description is based on the type specimen 

 (Mus. No. P 1 1 256) consisting of a complete cephalon and a nearly com- 



