92 
PALAEONTOLOGY OF NEW YORK. 
the test of favorably preserved specimens, and. more clearly seen upon casts 
of the lower surface. Occipital furrow shallow and narrow; occipital lobes 
transverse, inconspicuous; occipital ring broad and flat, becoming narrower 
upon the cheeks, and bearing a central tubercle. 
Cheeks depressed or broadly flattened on the summit beneath the orbital 
ridge, thence rounding in all directions to the broad border. 
Eyes moderately large, orbital ridge distinct; visual surface sub-crescentic. 
Pygidium sub-semi-elliptical, slightly emarginate behind. Surface convex. 
Axis elevated, arched, longitudinal furrows deep; width on the anterior 
margin about one-third the width of the shield; annulations seven or eight, 
slightly flattened and with a gentle retral curve over the axial line. 
Pleurce sloping evenly to the margin, and bearing five or six sulcate annu¬ 
lations, which are separated by broad, shallow furrows, the anterior and 
posterior limb being of about equal size. The annulations become extinct 
at the broad, smooth, sloping border. 
Surface of the test smooth, or covered with fine granules or obsolescent 
tubercles. Upon the glabella, cheeks and frontal border the ornamentation 
is flxint; upon the pygidium it is more conspicuous, each pleural annulation 
bearing two rows of sharp granules, one on each limb. The axis is covered 
with scattered granules. 
Dimensions. A fragment of the cephalon, consisting of the intra-sutural 
portion, has a length of 11 mm., a width between the eyes of 7.5 mm. An 
average pygidium measures 11 mm. in length, and 18 mm. in width. 
Observations. This species was erected upon detached fragments of cephala 
and separate pygidia occurring in comparative abundance associated in the 
Schoharie grit. In many features these parts are closely allied to those of 
Proetus Conradi, also an abundant species and intimately associated with this. 
The differences in the two forms are as follows; In Proetus angustifrons (a) the 
glabella is longer, more rapidly tapering and less distinctly lobed; (b) the 
summit of the cheeks is rounded and the lateral slopes less abrupt; (c) the 
