2r> 2 University Geological Survey of Kansas. 



probability the specimens did not come from this state. How- 

 ever, a specimen in our collection agreeing with the species was 

 obtained in the state, and probably from the Benton, though 

 possibly from either the Niobrara or Fort Pierre. 



CORAX. 



The genus Corax is confined wholly to the Cretaceous, and 

 is }'et incompletely known. Its distinction from Galeocerdo, 

 under which name some of its species have been described, is 

 based upon the solidity of the teeth — those of Galeocerdo have 

 a hollow cavity within. The teeth are small, compressed, more 

 or less triangular, with marginal serrations, though this charac- 

 ter may be more or less wanting in young individuals. They 

 vary not a little in shape in the same individual. In some the 

 crown is nearly bilaterally symmetrical, but they more usually 

 have the crown directed more or less obliquely backward, the 

 anterior margin convex, the posterior more or less straight and 

 angulated. 



Three species of the genus are known in England — C. falcatus, 

 C. pristodontus , which is hardly distinct, and C. affinis. In ad- 

 dition, C. antiquus Desl., C. incisus Egert., C. Isevis Gieb. and 

 C. pygmxus Munst. have been described from Europe, and C. 

 crassidens Cope and (J. hartvelli Cope from the United States. 



Corax falcatus. Plate XXXI, figs. 1-40; plate XXXII, figs. 1-11. 



Corax falcatus Agassiz, Poiss. Foss., in, p. 226, pi. xxvi, f. 14, xxvi-a, ff. 

 1-15; Woodward, Cat. Foss. Fishes Brit. Mus., i, p. 424 (where additional 

 synonymy will be found) ; Proc. Geol. Assoc. , xin, p. 198, pi. vi, ff . 13-15— 

 Cenomanian and Turonian of England, France, Switzerland, Saxony, 

 Bohemia, Galicia, and Russia; Senonian of England and France; Cre- 

 taceous of Texas, New Jersey, and Mississippi ; Niobrara of Kansas. 



Galeocerdo falcatus Leidy, Ext. Vert. Fauna West. Terr., p. 301, pi. xvn. 

 ff. 29-42. 



The very variable shape of the teeth referred to this species 

 will be seen in plate XXXI, figs. 1-40. Possibly the specimens 

 there figured represent distinct species. C. {Galeocerdo) crassi- 

 dens Cope seems to be represented by fig. 24, and C. (Gcdeocerdo) 

 hartvelli Cope 12 by fig. 23. Possibly this species also includes 



12. Cret. Vert., p. 244. 



