314 



oiie-thii'd the length from the front, tapermg towards both 

 ends; flat, fnrrowed, abruptl}' deflected plenrte; regularly 

 and evenly rounded margin of pygidium ; pustidose surface. 



Found in almost all the beds, from near the top of the 

 Moscow shales to the Marcellus shales (often abundant). 

 Especially common in the Trilobite beds of Section 8, on the 

 Lake Shore and in Averv's f reek. 



Genus DALMANITES. Bareaxde. 



Sub-genus CEYPH^US. Green. 



[Ety. : KryplKun-fi. liidden.] 

 (1837: Journ. Acad. Nat. Sci.,Yo]. VII., p. 217.) 



"Genal angles produced into long, often laterally' com- 

 pressed and narrow spines. Posterior thoracic segments 

 produced and acute. Pygidium with Ave annulations and 

 five pairs of marginal lobes or spines. Terminal lobe more 

 or less develojied.'' (Hall : Pal. X. Y., Vol. TIL, p. xxxiii. ) 

 Cryph.4:i's BOOTHi. Green. (Fig.2r)7.) 

 (Pal. N. Y., Vol. VIL. p. 42, Pis. XVI., 

 XVLA.) 



Dis t in ic // y.s h ing- Characters. — Large 

 ce})halon. with broad, thin, blunt genal 

 spines, which normally reach the sixth 

 thoracic segment; large pear-shaped or 

 sub-pentagonal glabella; pygidium Avith 

 eleven flmbrije or spines, which are stout, 

 flat and pustulose. 



Found in the lower three or four feet 

 of the Moscow shales, at Sections 4 and 

 5 (rare); in the Encrinal limestone at 

 Section 5 (i-are) ; in the Lower shales of 

 Sections .'> to 8, and cm the Lake Shore, 

 it is sparingly represented, occurring 

 6o''oT;..'''^gid3''rn^ "S^^^illj ^y^th" Fhacops mwr. in the 

 cialkt).^^"'''' ^""^ """'^ Trilobite beds of Section 8, etc., it is 



Fig . 257. Cr yphceus 

 boothi. Outline of an 

 average adult specimen 

 (after Hall and Clarke). 



