362 GEOLOGICAL SURVEY OF THE TERRITORIES. 



Anchitheridce. 



This extinct family of three-toed, horse-like animals, has for its type 

 the genus Anchitherium, the first known species of which was described 

 by Cuvier under the name of Palceotherium aurelianense. Its remains 

 were obtained from the miocene tertiary deposits of France. Lartet 

 and DeBlainville call the same animal Palceotherium hippoides, or horse- 

 like Palseothere. 



In the Equine family the teeth have long crowns, which are gradually 

 protruded as they are worn away; in the Anchitherine family the teeth 

 have comparatively short crowns, which are quickly protruded and in- 

 serted into the jaws by long fangs. Their skeleton in general form 

 closely approximates that of the horse, and most nearly that of Hip- 

 parion. 



ANCHITHERIUM. 



This genus is represented in the miocene deposits of our Western 

 Territories by two species. 



Anchitherium Bairdi. — The remains of this species are comparatively 

 abundant, in association with those of oreodons, rhinoceros, &c, in the 

 mauvaises terres of White Eiver, Dakota. The skull of the species is 

 a miniature form of that of the horse, except that the face is propor- 

 tionately shallower. Its length is rather less than seven inches. The 

 size of the animal was about half that of the domestic horse. The spe- 

 cies was named in honor of Professor Baird, of the Smithsonian Insti- 

 tution. 



Anchitherium Condoni. — A second species is inferred to have existed 

 from a fragment of an upper jaw with a mutilated tooth, discovered by 

 the Rev. Thomas Condon, of Dalles City, on Bridge Creek, a tributary 

 of John Day's Eiver, Oregon. It was rather larger than the preceding 

 species, and is named in honor of its discoverer. 



HYPOHIPPUS. 



An extinct genus to which this name is given is represented by the 

 following species : 



Hypohippus affinis. — Established on a single tooth, indicating an ani- 

 mal about the size of the domestic horse. 



ANCHIPPUS. 



Another extinct genus, allied to the preceding, is represented by the 

 following species : 



Anchippus texanus. — The species is established on a molar tooth ob- 

 tained by the late Dr. Shurnard in Washington County, Texas. It was 

 found in digging a well at the depth of 50 feet in a sandstone supposed 

 to be of miocene age. The animal indicated by the tooth was rather 

 smaller than the ass. 



PAKAHIPPUS. 



A fourth genus of the extinct A nchitherine family, named as above, is 

 indicated by some teeth discovered by Professor Hayden in the plio- 

 cene sands of the Niobrara Eiver. The teeth resemble in their char- 

 acters those of Anchitherium more nearly than they do those of any of 

 the equine genera; nevertheless they exhibit more complexity than in 

 the former or any other member of the same family. 



Parahippus cognatus. — The species thus designated is established 

 upon an incomplete series of well-preserved teeth. The animal was 

 about a third less in size than the ass. 



