TRILOBITA—OPISTHOPARIA. 



301 



116. P. foUiceps Hall. (Fig. 1612.) Devonic. 



Genal angles broadly rounded. Glabella very convex, without 

 furrows. Eyes prominent, elevated to about the height of the 

 glabella. Pygidium without a flattened margin but with surface 

 convex and sloping abruptly to the sides. 



Onondaga of New York and Michigan. 



Fig. 16 12. Proetusfolliceps. 

 (After Hall.) 



Fig. 1613. rt, Proetus rowi; 

 cephalus. (After Hall.) 



117. P. macrocephalus Hall. (Fig. 1613,^7.) Devonic. 

 Glabella wide and pustulose; a single deep pair of glabellar fur- 

 rows extend from the anterior angle of the eyes to the neck 

 furrow. Genal spines thin, acute. . 



Marcellus-Tully of New York. 



118. P. rowi (Green). (Fig. 1613, a.) Devonic. 

 Glabella without a trace of lateral furrows except when the 



test is broken away, but with a pair of ovoid, disconnected basal 

 lobes, the occipital lobes. Eyes very large. Genal spines long. 

 Pygidium with a conspicuously thickened border. Surface smooth 

 cr faintly pustulose. 



Hamilton of New York, etc. 



119. P. missouriensis Shumard. Mississippic. 

 Glabella large, tapering slightly anteriorly. Fourth pair of gla- 

 bellar furrows strong, reaching the neck ring; third and second 

 pairs short; first pair obsolete. Pygidium semicircular, flattened- 

 convex, with width double the length, and with broad, slightly 

 concave margin. Test granulose. 



