TRILOBITA—OPISTHOPARIA. 



261 



15. C. matthewi Hartt. (Fig. 1552, c.) Cambric. 



Marginal border of cephalon and lobe in front of glabella 

 prominent. 



St. John group (Acadian) of New Brunswick. 



VIII. Atops Emmons. 



Cephalon semicircular, its anterior and lateral edges turned up- 

 ward. Glabella subquadrate. Free cheeks very narrow, the facial 

 suture running nearly parallel to the sides of the glabella. Axis 

 nearly as wide as the side lobes and ornamented with a medial row 

 of spines ; the lateral lobes with a median row of tubercles. Pygid- 

 ium small. 



Differs from Conocoryphe in having a more cylindrical and 

 longer glabella, small pygidium and 17 free segments. Lower 

 Cambric. 



16. A. trilineata Emmons. (Fig. 1553.) 



Cambric. 



Fig. 1553. Atops trilineata. (After 

 Emmons. ) 



Fig. 1554. Bathynotus 

 entire individual, X K' ^"*^ hypostoma 

 attached to doublure. (After Walcott). 



Entire surface granular. (Type of genus.) 

 Lower Cambric of New York and Quebec. 



