100 



CRETACEOUS AND TERTIARY FISH. 



Genus PLINTHICUS Cope. 



Plinthicus Cope, Proc. Boston Soc. N. H., XII, 1869, p. 316. Type Plin- 

 thicus stenodon Cope, monotypic. 



Known from thin and rather depressed teeth. Related to 

 Aetobatus, but differing in having the roots of the teeth project- 

 ing but slightly posterior to enameled surface. 



One species described, extinct. 



Plinthicus stenodon Cope. 



Plinthicus stenodon Cope, Proc. Boston Soc. Nat. Hist., XII, 1869, p. 316. 

 Shiloh, Cumberland Co., N. J. Miocene. 

 Hussakof, Bull. Amer. Mus. Nat. Hist., XXV, 1908, p. 33, fig. 10 (type). 



Dental plate greatly depressed, mostly with transverse or hori- 

 zontal teeth nearly straight or but slightly and rather evenly con- 



Fig. 53. — Plinthicus stenodon Cope. Charles Co., Md. (Thomas). 



