96 PALEONTOLOGY OF NEW YORK. 



Pleura flat for one-half their width, thence abruptly deflected to the lateral 

 margins Each segment is grooved by a sharply impressed furrow which 

 becomes obsolete at the articulating plane. 



Pyqidium semi-elliptical, sometimes a little produced at the posterior extremity. 

 Length to width as 4 to 5. Surface elevated, flattened above, deflected at 

 the sides. Border broad, widening posteriorly and strongly curved upward. 



Axis convex, tapering evenly to a blunt, somewhat elevated termination 

 just within the margin, and bearing thirteen or fourteen annulations, which 

 an- marked by a faint, impressed longitudinal groove or line just above the 

 axial furrows. Each annulation is obliquely flattened and makes a double 

 curve in crossing the axis, sloping forward for about one-fourth the distance; 

 being angulated at that point, just above the impressed line, and thence 

 bending backward in a broad curve to the axial line, along which is a series 

 of small nodes giving the axis the appearance of being medially angulated. 



Pleura flattened or very gently convex for about one-third of their width, 

 thence rounding to an almost vertical slope upon the sides. Upon the poste- 

 rior area the slope is less abrupt. They bear twelve annulations, which are 

 separated by moderately broad furrows, and each is distinctly grooved for its 

 entire length by a fine impressed line, visible upon the cast as well as on 

 the dorsal surface. The anterior annulations encroach for a short distance 

 upon the border. 



An bypostoma found in association with abundant fragments of this species is 

 sub-triangular, centrum elongate, regularly convex, anterior margin narrow 

 and deflected; anterior angles broadly sub-auriculate ; postero-lateral depres- 

 sions long but not continuous; posterior sulcus prominent and posterior 

 lingua short. 



Surface. Ornamentation. The cephalon is covered with fine tubercles and 

 granules, which are most abundant upon the glabella, and are also faintly 

 visible upon the segments of the thorax and the annulations of the pygi- 

 be inter-annular grooves of the pygidium appear to be punctate. 



