loo Nor til American 



surface smooth, or even apparenlly polished, and showing no traces of 

 lenses under a good magnifier ; palpebral lobes convex, but resting like a lid 

 upon each eye. Cheeks sub-trigonal, declining abruptly from the eyes! 

 lateral margins turned downward, and forming below a sharp edge, which con. 

 tinues back along the lower margin of the posterior spine-like appendages ; 

 above this there is a vertically flattened, or even concave zone or belt, ex. 

 tending from near the front part of the glabella around the outer side 

 of each cheek, and becoming a shallow^ furrow as it passes back upon 

 the spines, along which it seems to be more or less marked nearly to 

 their pointed extremities ; between this vertically flattened band and the 

 eyes, there is another nearly horizontally flattened, or outw^ardlj'' sloping 

 zone extending around each cheek from near the front posteriorly, so as to 

 unite with the lateral connections of the neck-furrows behind, and continues 

 as a single furrow^ along the upper margin of the posterior spines, thus leav- 

 ing a more or less defined mesial ridge between these tw^o furrow^s the entire 

 length of the posterior lateral spiniferous appendages, as well as around the 

 cheeks, to near the front of the glabella ; posterior margins of the cheeks, 

 behind the continuations of the neck-furrow, very prominent, or forming 

 a thickened rim. Facial sutures extending obliquely forw^ard and outward 

 from the anterior side of the eyes ; and again curving inw^ards, so as to cut 

 the anterior margin nearly on a line with the anterior inner extremity of 

 the eyes ; from the posterior end of the eyes, directed obliquely outwards 

 and backw^ards, so as to intersect the posterior margin nearly midway be- 

 tween the neck-segment and the sub- spiniferous lateral posterior append 

 ages. 



Thorax only known from a few of the posterior segments, which show 

 the mesial lobe to be wider and distinctly more prominent than the lateral 

 lobes, w^hich are flattened near the mesial lobe, aud abruptly deflected down- 

 wards near the middle ; segments divided by a furrow near the anterior side 

 from the knee inw^ards, and flattened in the direction of the axis at the 

 rounded outer extremities. 



Pygidium semi-elliptic, slightly wider than long, and rather convex, dis- 

 tinctly narrower and a little longer than the cephalic shield, narrowing back- 

 wards, and narrowly rounded at the posterior extremity. Mesial lobe prom- 

 inent, a little flattened on each side, and narrower than the lateral lobes, 

 from which it is distinctly separated by broad strong furrows ; tapering 

 gradually backwards and terminating rather abruptly near one-third its own 

 length from the posterior margin, so as to leave a broad, nearly flat, or more 

 or less sloping smooth border, w^hich extends along each side the whole 

 length of the pygidium, but becomes narrow^er anteriorly ; segments of the 

 mesial lobe 17 or 18, well defined, rounded, and very nearly or quite straight. 

 Lateral lobes more depressed, and about one-third or one-fourth wider than 

 the mesial lobe, rounding dowm rather abruptly to the lateral margins ; seg- 

 ments 9 or 10, rounded, simple, and separated by distinct furrows ; all ter- 

 minating abruptly at the inner edge of the broad smooth marginal zone. 

 Entire surface apparently very nearly smooth. 



