TRILOBITA— PROP ARIA, 



329 



187. D. (Odontocephalus) selenurus (Eaton). (Fig. 1646.) 



Devonic. 



Frontal border of cephalon with nine spines ; genal angles obtuse 

 or produced into minute spines. Pygidium ending in two diver- 

 gent spines, their bases distant ; pleura eight. 



Onondaga of New York, etc. 



Fig. 1645, Dalmanites calypso. 

 (After Hall and Clarke.) 



Fig. 1646. Dalmanites selenurus. 

 (After Hall and Clarke.) 



LXX. Cryph.eus Green. 

 A Dalmanites in which the genal spines are much prolonged; 

 glabellar furrows three ; pleura of pygidium prolonged into five 

 conspicuous spines. Devonic. 

 188. C. boothi Green. (Fig. 1647, a, 6.) Devonic. 



Fig. 1647. ^> ^t CryphcBus boothi, entire specimen, X %> ^"^ pygidium ; c, var. cal- 

 liteles. (Copies from Hall and Clarke. ) 



Genal spines broad, lying nearly in a vertical plane, and reach- 

 ing to the sixth thoracic segment. Pygidium with 11 flat, thick, 

 pustulose spines. (Type of genus.) 



Hamilton group of New York, Pennsylvania and Michigan. 



