204 PALEOZOIC PALEONTOLOGY. 
rows; about as wide behind as its length, including the occipital 
segment, much narrower in front; the frontal and three pairs of 
lateral, glabellar lobes separated by three pairs of glabellar furrows, 
of which the anterior pair is much the faintest and shortest, each 
member of the second pair extends about one-fourth the distance 
across the glabella, slightly’ curved posteriorly, the posterior pair 
deeper and wider than either of the others, each member extending 
about one-third of the distance across the glabella and directed ob- 
liquely backward. Occipital furrow deep and prominent, connecting 
with the dorsal furrows and less conspicuously with the marginal 
furrows of the posterior margin of the fixed cheeks, arching slightly 
forward at the middle of the glabella. Occipital segment well de- 
fined, arching a little forward, about as high as the most prominent 
portion of the glabella in front. Fixed cheeks convex, provided with 
a deep, broad furrow along their posterior margin. 
Pygidium wider than long, more or less subtrigonal in outline, but 
with the anterior margin broadly rounded. Axis well defined, convex, 
extending nearly to the posterior margin, with five or six transverse 
segments, which grow fainter posteriorly. The plure convex, each 
with about five segments, which are furrowed distally. 
Whole surface of the test minutely granular. 
Remarks.—Fragments of this species are common in the Trenton 
fauna of New Jersey, but no complete individuals have been observed. 
This species is most closely allied to the common Cincinnatian species 
of Southern Ohio and Indiana, which Clarke has referred to* C. 
callicephala Green. ‘The Trenton species, however, can always be 
distinguished from it by the grooving of the segments of the plure 
of the pygidium. 
CERAURUS PLEUREXANTHEMUS Green. 
Plate XV., Fig. 28. 
1847. Ceraurus pleureranthemus Hall, Pal. N. Y., vol. I., p. 242, pl. 
65, figs. 1 a—n, pl. 66, figs. 1 a—h. 
Description—Head_ crescentiform in outline, with the posterior 
lateral angles extended into long, curved, genal spines, which are 
attached to the fixed cheeks. Free cheeks irregularly triangular in 
* Pal. Minn., pt IL., p. 699. 
