156 Field Columbian Museum — Geology, Vol. II. 



" The above specimens are all from the Upper Cretaceous of Western 

 Kansas."* 



" Nyctosaurus, gen., nov." A second genus of American Pterodactyls 

 is represented in the Yale Museum by several well-preserved specimens. 

 This genus is nearly related to Pteranodon, but may be readily distin- 

 guished from it by the scapular arch, in which the coracoid is not co ossi- 

 fied with the scapula. The latter bone, moreover, has no articulation at 

 the distal end, which is comparatively thin and expanded. The type of 

 this genus is Pteranodon gracilis Marsh, which may now be called Nycto- 

 saurus gracilis. It was a Pterodactyl of medium size, measuring about 

 eight to ten feet between the tips of the expanded wings. Its locality is 

 in the Upper Cretaceous of Western Kansas. The type specimens of all 

 the above species are preserved in the Museum of Yale College." f 



" In the same geological horizon with the gigantic forms (Pterano- 

 don beds) the remains of a single small Pterodactyl have been found. 

 Th;s animal was more diminutive than the Jurassic species \Dermodactylus 

 montanus], having a spread of wings not more than three or four 

 feet. The jaws were proportionally more slender than in the larger Cre- 

 taceous species, and no teeth have been found with them. The humerus 

 had a small head and an enormous radial crest, which curved downwards. 

 The scapula and coracoid were firmly ankylosed. Some of the trunk 

 vertebrae have very long transverse processes, or ankylosed ribs, curved 

 backward. Some dimensions of this specimen are as follows : 



Length of humerus 62 



Greatest diameter of head 12 



Transverse diameter across radial crest 30 



Greatest diameter of distal end 16 



Vertical diameter of humeral glenoid cavity 13 



Transverse diameter 6 



" This species may be called Pteranodon nanus. Its known remains 

 were found by Mr. S. W. Williston, in the Middle Cretaceous of Western 

 Kansas." % 



"The name Nyctosaurus, applied by the writer to this group, appears 

 to have been preoccupied, and hence may be replaced by Nyctodactylus. 

 The only species known is Nyctodactylus gracilis.'''' jj 



It is seen that but five vertebrae are referred to the sacrum of the 

 type of Nyctosaurus gracilis ; if this be a real character one would not 

 question the distinctness of the species. Inasmuch as Pteranodon has 

 six vertebrae in the sacrum and one or more lumbars or false sacrals, as in 



♦Marsh, 1. c, p. 509. 



t Marsh, Amer. Journ. Sci. Dec, 1876, p. 480. 



% Marsh, Amer. Journ. Sci. April, 1881, p. 343. 



II Marsh, Amer. Journ. Sci. April, 1881, p. 343, footnote. 



