414 GEOLOGICAL SURVEY OF THE TERRITORIES. 



M. 



Caudal, width of basis diapophysis 0245 



Caudal, "width between chevron rami 0115 



Pterygoid tooth, height of crown 0125 



Pterygoid tooth, diameter of pedestal 013 



This species was found by Professor Mudge, near the locality of the 

 Liodon mudgei, six miles south of Sheridan, Kansas. 



It is only necessary to compare this species with C. intermedins, Leidy,* 

 as the G. iguanavus and G. propytkon have depressed vertebral centra. 

 Those of the first are round, of the present compressed. The G. inter- 

 medins also agrees with the two others in the obliquity of the articular 

 faces to the transverse plane of the centrum ; in the present species 

 these planes are parallel. This species is also larger than the G. iguan- 

 avus, Cope; the G. intermedins is smaller. 



There is another species from New Jersey to which it is more nearly 

 allied, a vertebra of which I have described under the head of Liodon 

 Icevis (Trans. Amer. Philos. Soc, 1869, p. 205,) and figured 1. c, Tab. 

 V, Fig. 5, under the erroneous name of Macrosaurus validus. This 

 probably does not belong to the Liodon Icevis, which does not possess 

 the zygosphen articulation, but is most likely allied to the present 

 species, and a true Glidastes. When compared with a vertebra from 

 the same position in the column, as determined by the position of the 

 diapophyses, the articular faces are still more compressed, and the in- 

 ferior surface of the centrum, instead of being regularly convex, forms 

 a plane separated from lateral concavities by an obtuse angle. There 

 is less expansion of the margins of the cup and ball. The size is also 

 greater. I propose to distinguish this species as Glidastes antivalidus, 

 Cope. It is from the darker stratum of the green sand, near Medford, 

 New Jersey. 



TELEOSTEI. 



Physostomi. 



SAURODONTED^E, (COPE.) 

 (Proceed. Amer. Philosoph. Soc., November, 1870, p. 529.) 



The genus Saurocephalus of Harlan and its allies have been referred 

 to the neighborhood of the Acanthopterygian family of the Spliyramidce 

 by Professor Agassiz in his Poissons Fossiles, after having been re- 

 garded by Harlan and Hays as reptilian. This was an important step 

 in the right expression of its affinities ; but I take the present oppor- 

 tunity of making another progress in the true interpretation of its rela- 

 tions, favored as I am by the opportunity of examining new material 

 not accessible to former authors. My conclusion, it will be observed, 

 differs widely from that heretofore maintained. 



Some years after Harlan's description of Saurocephalus lanciformis 

 appeared, Dr. Hays described a second species under the name of Sau- 

 rodon Jeanus. This I believe to represent a genus distinct from the for- 

 mer. A third genus more remote is characterized in the present article. 



The characters of first importance which may be assigned to these 

 genera are : Vertebrae short, numerous ; their neural arches united with 

 centrum by persistent suture. Tail vertebrated or heterocercal. Supe- 

 rior arch of the mouth formed by the short premaxillaries and long 



* Proc. Acad. Nat. Sci., Philadelphia, 1870, p. 4. 



