342 University Geological Survey of Kansas. 



and those supporting the fin are very much so. The last 

 vertebra is succeeded by a fan-shaped expansion of bone or 

 urostyle, which presents a well-marked lateral ridge on the side 

 exposed. The neural arches fit into pits at their bases, and in 

 the caudal region they have lamina of bone projecting down 

 the sides, forming yoke-like articulations with the centra. The 

 arches are expanded at their bases and are largest in the anterior 

 region, where they are directed backward but slightly, while in 

 the region of the fiftieth posterior vertebra the arches are very 

 slender and directed strongly backward. The manner of attach- 

 ment of the haemapophyses cannot be made out with certainty, 

 although they were probably inserted in gomphoses, as are the 

 neurapophyses. The ribs are long and slender and slightly ex- 

 panded at the proximal extremity. They seem to be inserted 

 in pits on the sides of the centra. The caudal fin is homocer- 

 cal, and is composed of numerous rays which articulate with the 

 centra by means of the yoke-like articulation mentioned above. 

 Toward the distal extremity these rays gradually split up into 

 many small filaments, which makes this portion very difficult 

 to collect in perfect condition. One of the smaller specimens 

 of this genus shows an imperfect impression of the dorsal fin. 

 It seems to have been composed of short spines rather far 

 separated and extending along the greater extent of the back. 

 There are no remains of the other fins sufficiently well pre- 

 served to show their important characters. 

 The following species are known : 



Anogmius contractus Cope, Niobrara Cretaceous, western Kansas. 

 Anogmius aratus (?) Cope, Niobrara Cretaceous, western Kansas. 

 Anogmius evolutus Cope, Niobrara Cretaceous, western Kansas. 

 Anogmius polymicrodus Stewart, Niobrara Cretaceous, western Kansas. 



Anogmius polymicrodus. Plate LXIV; plate LXV, figs. 1-7; plate LXVI; 

 plate LXVII, fig. a. 



Beryx polymicrodus Stewart, Kans. Univ. Quar., vol. vn, pp. 195,196. 



This species was first described by myself as Beryx polymi- 

 crodus from some fragments of jaws collected in western Kansas 

 several years ago, but the material was too fragmentary to give 

 any idea of the animal. During the past summer the geolog- 



