20 Bulletin American Museum of Natural History. [Vol. XIX, 



collection show that the front border is bevelled off on both 

 sides, as a board may be bevelled off by a carpenter's plane. 



At the middle of the length of the fin the component rays 

 make an angle of about 22° with the edge. At the distal end 

 the angle is somewhat smaller. 



This fin must have belonged to a large and powerful fish, 

 of which no other parts are known. 



Dr. Loomis in his paper on Kansas fishes holds that this fin 

 formed one lobe of the caudal fin of some species of Proto- 

 sphyrcBna; and in his restoration of Protosphyrcena he recon- 

 structs the caudal fin from this specimen. This is, however, 

 manifestly an error. In the caudal fin of fishes the right and 

 left halves of the constituent rays diverge slightly at their 

 proximal ends, so as to receive between them the hypural 

 bones. They are also each drawn out to a point. In the 

 pectoral fins the two portions of the ray not only diverge 

 strongly, but each half is broadened so as to form two pro- 

 cesses. One of these is directed toward the corresponding 

 surface of the fin, while the other is brought into close con- 

 tact with the small bones at the distal ends of the baseosts. 

 The fin known as ProtosphyrcBna gladiiis has the same struc- 

 ture as that of the pectoral fin of ordinary fishes and of other 

 species of Protosphyrcena. 



PLETHODID^. 



Anogmius Cope. 



This genus was erected by Prof. Cope in 1871 (Proc. Amer. 

 Philos. Soc, XII, p. 170), the type species being A. contractus , 

 and the type specimen consisted of a large number of vertebrae 

 representing a fish believed to be about four feet in length. 

 The vertebrae were in the Agricultural College, at Manhattan, 

 Kansas, and had been collected by Prof. B. F. Mudge. These 

 vertebrae are further described on page 354 of the volume re- 

 ferred to. This description is repeated on page 241 of the 

 same author's 'Vertebrata of the Cretaceous Formations of 

 the West'; but on page 220A, evidently written later, he 

 records his conclusion that the genus in question was really 



