272 



NORTH AMERICAN INDEX FOSSILS. 



ital spine present. Sides of glabella nearly parallel. Pleural and 

 pygidial spines extending backward abruptly, not curved as in N, 

 serratus. Surface as in N. superbus. 

 Middle Cambric of Utah. 



Fig. 1568. 



Olenoides wasatchensis, pygidium and central portion of head, imperfect. 

 (After Walcott. ) 



XVIII. Olenoides Meek. 

 Glabella elongate with subparallel sides. Eyes elongate. Thorax 

 with seven or more segments. Pleural grooves broad. Spines 

 present on the genal angles, on ends of pleura, on each segment of 

 the axis and on the neck ring. Pygidium broad, with all annula- 

 tions terminating in short spines. Middle Cambric. 



Fig. 1569. o,b, Olenoides viarcoui, pygidium and cephalon, the latter crushed ; c, 

 d, O. curticei ; e, Agraulus quadrangularis, restored ;/, g, Strenuella strenua. (/, g, 

 after Shimer ; <*, after Grabau ; the others after Walcott. ) 



41. 0. marcoui Whitfield. (Fig. 1569, a, 6.) Cambric. 



Pygidium with flattened spines upon the margin and with nodes 



upon the four anterior rings of the axis. It lacks the grooved 



