304 NORTH AMERICAN INDEX FOSSILS. 



Axis of thorax ornamented with five longitudinal rows of small 

 tubercles and the pleura with two rows. 

 Waverly of Ohio. 



127. P. meramecensis Shumard. Mississippic. 

 Pygidium slightly wider than long, very convex; median lobe 



. slightly narrower than the side lobes, with about 13 segments 

 which are quite convex centrally, becoming flattened on the sides; 

 side lobes strongly curved downward. Surface strongly granulose. 

 Upper Waverly of Ohio, Iowa and Missouri. 



128. P. missouriensis Shumard. Mississippic-Carbonic. 

 Thorax of 11 segments; pleura rounded, not furrowed. Pygid- 

 ium elevated, with width greater than length. Surface finely 

 punctate. Margin rather broad and smooth. Width of axis equal 

 to about three fourths of a lateral lobe; annulations about 18. 

 Lateral lobes and axis rather strongly arched transversely. Length 

 of pygidium .7 inch ; greatest width .8 inch. 



Waverly of Ohio; Coal Measures of Missouri. 



129. P. major Shumard. Carbonic. 

 Entire individual elongate-oval in outline. An elongate indi- 

 vidual measures in total length 32 mm., width 16 mm., length of 

 cephalon 13.6 mm., thorax 6.4 mm., pygidium 12 mm. Genal 

 spines long, extending to the pygidium. Glabella subquadrangular, 

 wider than the cheeks; fourth glabellar furrow strong, third and 

 second weak, first absent. Eyes large. Pygidium slightly longer 

 than wide; median lobe high, arched longitudinally, compressed 

 and furrowed on each side, with about 23 segments; lateral lobes 

 broader than median one, turned abruptly downward at the sides, 

 but sloping behind more gradually to the smooth, flat border. 



Upper Coal Measures of Missouri, Kansas and Nebraska; Car- 

 bonic of Colorado, Montana, etc. 



XLIX. Griffithides Portlock. 



Oval. Glabella expanded anteriorly, depressed and narrowed 

 back of the middle; basal lobes present. Eyes small. Thorax 

 with nine segments. Pygidium rounded, with 13 segments. Differs 

 from Phillipsia in the shape of the glabella. Mississippic-Carbonic. 



I 



