94 North American 



terior lateral lobes small, much depressed, and isolated by the oblique lateral 

 furrows in the front being so directed as to intersect the neck-fuiTow ; im- 

 mediately in front of these there are on each side famt traces of anotbtr 

 small, very obscurely defined, lateral lobe ; anterior lobes ovate, ventricose, 

 and comprising more than nine-tenths of the whole ; neck-furrow deep and 

 and broad ; its continuation across tbe posterior side of the cheeks distinct, 

 straight, and terminating at the lateral furrows of tbe cheeks ; neck-segment 

 prominent, twice the size of the thoracic segments, and equaling the greatest 

 transverse diameter of the glabella in front, but more depressed. 



" Eyes in the form of somewhat oval, ventricose tubercles, considerably 

 lower than the glabella, from which they are separated by rather wide, dis- 

 tinct depressions, placed about half their length in advance of the posterior 

 margin of the cheeks, and without visible facets ; palpebral lobes depressed, 

 not covering the eyes, but merely connecting with their inner sides, so as to 

 leave the visual area forming an almost isolated tubercle. Cheeks sloping 

 from the eyes into a broad, deep marginal sulcus, which is not continued 

 around the front of the glabella, but extends back a little upon the lateral 

 spine ; outside of this there is a thick, distinctly striated marginal rim. 

 which becomes very nearly obsolete around the front of the glabella. Fa- 

 cial sutures cutting the anterior margin nearly on a line with the eyes, but 

 curving so as to leave a small semi-circular wing on each anterior lateral 

 margin of the glabella ; behind they intersect the posterior margin of the 

 cheeks about midway between the lateral angles and the neck-segment, but 

 nearer the latter. Thorax nearly as long jis the glabella, exclusive of the 

 neck-segment, distinctly trilobate ; axial lobe slightly wider than the lateral 

 lobes, rounded a d rather prominent ; its segments narrow and straight, or 

 not arched forward. Lateral lobes more depressed, somewhat flattened on 

 the inner side, rounding down to the lateral margins ; segments duplicated 

 by a nearly mesial furrow extending from their inner ends out to or a little 

 beyond the undefined knee, beyond which they are obliquely flattened for 

 folding together, and rounded at their extremities. 



" Pygidium a little more than one-fourth wider than long, rather dis- 

 tinctly convex, rounded behind, and more or less straight in front, with an- 

 terior lateral angles obliquely truncated and a little rounded. Mesial lobe 

 very prominent and w^ell defined, rounded above, and a little flattened or 

 furrowed on the sides ; as wide anteriorly as the lateral lobes, tapering and 

 declining somewhat posteriorly to an abrupt, obtuse, prominent termination ; 

 about half its own greatest anterior breadth within the flattened margin ; 

 segments fourteen or fifteen, distinctly defined, smaller than those of the 

 thorax. Lateral lobes depressed below the mesial lobe, somewhat flattened 

 on the inner side, and sloping to the rather narrow and more flattened bor- 

 der ; segments ten, somewhat oblique, well-defined for three-fourths of the 

 distance out, and thence less distinctly so, to within a short distance of the 

 margin ; a few^ of the anterior ones with an obscure longitudinal furrow. 

 Surface granular, the granules being largest on the posterior portions of the 

 glabella, palpebral lobes and neck-segment. On the segments of the axial 



