OF DENISON UNIVERSITY. 
57 
This name was applied to proetoid forms with fimbricated pygidium. 
As amended by Angelm, this genus includes both forms of pygidia 
where the glabella is short and ovoid, having distinct basal lobes and 
two pairs of faint obsolescent, lateral furrows in front of the lobes. As 
stated by Hall the genus connects Cyphaspis and Proetus and (as he 
might have said) introduces Brachymetopus. 
Diagnosis. Cephalon as in Cyphaspis [semicircular, genal angles 
produced into spines. Glabella strongly arched, short and narrow, 
with two small pyriform basal lobes, bounded on all sides by deeply 
impressed furrows. Anterior lateral furrows obsolete] the frontal area, 
however, being more deeply concave and the lateral glabellar furrows 
stronger and generally duplicate. Thorax composed of not less than 
seven narrow segments and probably more. Axis wide. Pygidium 
Proetoid, relatively large, bearing from eight to twelve annulations 
upon the axis and eight or nine upon the plurse. These annulations 
extend to the margin and are conspicuously duplicate their entire 
length. Surface turbercled or smooth.” The genus extends from the 
Upper Helderberg to the Hamilton, and, as we now show, to the close 
of the Chemung in Ohio.* 
PHAETHONIDES OCCI DENTALIS, sp. n. 
(Plate I, Fig. lo, a, b.) 
Glabella two-thirds as long as the head-shield not including the 
neck segment, sub-oval, quite tumid behind but flattened anteriorly, 
highest point rather behind the middle, distinctly separated by a groove 
from the small lateral lobes, also marked near the anterior third by a 
slight depression at the sides ; head-shield in front of the glabella grad- 
ually descending to the rather narrow somewhat elevated border which 
is set off by a broad ill-defined groove ; eyes apparently distant from 
the glabella, cervical segment narrow, separated from the glabella by 
a narrow deep groove, entire surface tuberculate. (The specimen 
does not preserve the entire shield, but it was evidently much more 
broadly rounded than is usual in Brachymetopus.) 
Pygidium semi-elliptical, elevated, consisting of about sixteen 
■-’-In the Trans, of N. Y. Acad. Sci., June 4th 1888, Mr. Vogdes describes 
from the Waverly of Sedalia, Mo., Griffithides ? sedaliensis, Vogd , which seems 
to belong to the present group. 
