60 UNGTJLATA. 



monodactyle character of one species, and the structure of the cranium 

 and dentition is, however, so essentially equine, that it is here placed 

 in the present family. The upper premolars are as complex as the 

 true molars, and all the cheek-teeth are of an extremely hypsodont 

 type, the cement completely filling the valleys ; the lower molars 

 are crescentoid, and there is scarcely any distinct third lobe to m . 3. 

 The digits are either one or three in number. 



Genus HIPPARION, Christol l . 

 Syn. Hippotherium, Kaup 2 . 



Dentition: I. |, C. \, Pm. |, M. ?. The first upper cheek-tooth, 

 which appears with the milk-series, and apparently has no prede- 

 cessor, is usually shed before the animal is adult. The anterior 

 " pillar " 3 in the upper cheek-teeth is disconnected from the anterior 

 inner " crescent " for at least three quarters of its length ; and there 



JFig. 11. 

 pin. 4. 



pm. 3. 





/. d. e. c. 



Hipparion, sp. 4 Polished section of three right upper cheek-teeth, in a frag- 

 ment of the maxilla ; from the Siwaliks of Perim Island, Gulf of Cam- 

 bay, India. Indian Museum, Calcutta (no. 0. 273). a. Posterior, and 

 b, anterior outer crescent ; c, anterior, and d, posterior inner crescent ; 

 e, anterior, and /, posterior pillar. (From the ' Palseontologia In- 

 dica.') \. 



1 Ann. Sci. Indust. Mid. France, vol. i. p. 180 (1832), teste Christol. 



2 Neues Jahrb. 1833, p. 327. As a subgenus. 



3 For the definition of the terms employed in the description of the cheek- 

 teeth of the EguidcB, see ' Palaeontologia Indica ' (Mem. Geol. Surv. Ind.), 

 ser. 10, vol. ii. pp. 73, 74, and the accompanying woodcut (fig. 11). 



4 If this form be specifically distinct, it has been proposed that it should be 

 known as H. feddeni, Lydekker, ' Palaeontologia Indica,' ser. 10, vol. iii. p. 16 

 (1885). 



