92 PALEONTOLOGY OF NEW YORK. 



the test of favorably preserved specimens, and more clearly seen upon casts 

 of tin' 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. 



Pfgidium 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. • 



Pleura 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 i be 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 faint ; 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 -rit. In many features these parts are closely allied to those of 

 Proelus 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 



