330 GEOLOGICAli SUEYEY OF THE TEREITOEIES. 



The tibia is a narrow bone, exiDanded at both ends ; the fibula is like 

 that of Flesiosaurus, but wider, or i^artly discoid. It has been known 

 to naturalists, but not determined. Thus, I figured it for L'wdon Jcevis* 

 and Leidy figured it for an Upper Mississippi species.t 



There was for a considerable time doubt as to the structure of the 

 anterior limbs in this order, some authors asserting their ambulatory, 

 others their natatory character. Dr. Leidy inferred that they were 

 flippers, after an examination of a htimerus from ]\[ississippi. This 

 ttirns out to belong to a turtle, {Protostega tuherosa.Co'pe:) hence the 

 first real determination of the character of these members was made by 

 the writer in his descrii)tion of the four limbs of CUdastes propytlion^ 

 the first species in which they were well rei)reseuted by specimens. 



CLIDASTES, Cope. 

 Proc. Acad. Xat. Sci., Phila., 186S, p. 233 ; Trans. Amer. Philos. Soc, 1370, p. 211. 



Vertebrae with the zygosphen articulation. [Palatine bones flat and 

 alate ; the teeth not exposed at their bases unequally. This point has 

 not been observed iu the type species C. iguanavus.] 



Clidastes cineriarux, Cope, (Proc. Amer. Philos. Soc, 1S70, 583.) — 

 Two individuals from di ft er en t points near the jSTorthFork of the Smoky 

 Hill Eiver, Kansas. 



The largest species of the genus. 



Cledastes yy:\ia>t:i. Marsh, (Amer. Jour. Sci. and Arts, June, 1871.) — 

 From two individuals fi^om the Smoky Hill Eiver and its North Fork. 

 A small species. 



Cledastes pr:\nxrs. Marsh, [loc. cif.) — From one individual from the 

 Smoky Hill Paver. The smallest known Jlosamuroid, according to Pro- 

 fessor Marsh, reaching a length of only 12 feet. 



EDESTOSAUPtUS, Marsh. 

 Amer. Jour. Sci. and Arts, 1871, June. 



Tertebrie with the zygosphen articulation ; palatine bones narrow, 

 partly vertical ; the bases of the pterygoid teetli exposed on one side, or 

 pleurodont. (It is uncertain whether the type of Clidafites presents this 

 structure or not.) 



Edestosaerus tortor, Cope, (Proc. Amer. Philos. Soc, 1871, De- 

 cember.) — A slender species of some 30 feet iu length, with a narrow, 

 pointed head of 2^ feet. Its teeth are compressed, and with a cutting 

 edge fore and aft, and were 18 in number on the under jaw; the palate 

 was armed with 11 teeth. 



Found near Fossil Spring. 



Edestosal'res stenops. Cope, {loc. cit.) — A species not unlike the 

 last, founded on one individual of rather heavier proportions. Its 

 prominent character is the narrowness of the tace in front of the orbits, 

 the prefrontal bones being nearh' vertical instead of horizontal. 



From Fossil Spring. 



Edestosal'RLS dispar. Marsh, (Amer. Jonr. Sci. and Arts, June, 

 1871.)— Smoky Hill Eiver. 



Edestosae'rus YELOX, Marsh, (loc. cit.) — Xear the North Fork of the 

 Smoky Hill River. 



* Trans. Amer. Philos. Soc, 1869, p. 205. 



t Cretaceous Reptiles U. S.,Tab. YIII, Fig. 10. 



