370 University Geological Survey of Kansas. 



but little if any from the markings on the front and sides of the 

 bone. The markings on the inferior surface are similar to those 

 on the sides, and do not become larger and more scattered, as 

 in P. recurvirostris . The bone is pointed at the apex, giving a 

 more acute shaft than in P. nitida, in which the rostrum con- 

 tracts suddenly to a tip, but less acute than P. recurvirostris, 

 where the shaft is more slender and the apex drawn to a more 

 slender point. The markings are not so sharply defined and 

 inosculate with each other more often than in the species just 

 mentioned, especially on the anterior portion and sides. Nio- 

 brara Cretaceous, western Kansas. Collector, E. P. West. 



There are remains of several pectoral fin-spines, and an- 

 other which may be the pelvic fiii, that I will refer to this 

 species with doubt. They are much smaller than those de- 

 scribed by Cope as 'Pelecopterus,' and also differ from these in 

 other minor details. Doctor Crook mentions in his paper on 

 the ' ' Kansas Cretaceous Fishes ' ' 128 that he had a right and a left 

 pectoral fin-spine of this species in his possession at the time of 

 preparing his paper, but failed to describe them, which makes 

 the determination of the remains before me very difficult. 



The fin is composed of parallel rods of bone, which are very 

 slender at the posterior side, but toward the anterior border 

 they become broader and slightly curved. The anterior 

 border is nearly straight for a distance of 45 mm., when it 

 begins to assume an undulated appearance, which becomes 

 less marked and farther separated beyond the center, and prob- 

 ably finally disappears before the extremity is reached. In P. 

 nitida these undulations assume a dentate appearance, and con- 

 tinue thus to the extremity, while in P. gladius and P. chirurgus 

 this border is devoid of such undulations. This portion is cov- 

 ered with a thin layer of enamel-like substance, which seems to 

 be thickest on the apices of the undulations. The spine is 

 moderately broad at the base, where there are forty or more 

 rods, but becomes more narrow distally. There are portions of 

 probably seven basiosts, the anterior ones of which are probably 

 paired. These are all provided with well-rounded condylar 



128. Uber ein. Enoch, fis. a. d. mitt. Krei. Kans., Paleontographica, 1892, 110. 



