10 TJNGULATA. 



Lophiodon minimus, Fischer \ 



Syn. Pachynolophus minimus, Gervais 2 . 



This small species is about the size of Pachynolophus isselanus. 

 Hah. Europe. 



36836, 39837-8. The second lower true molar, the second lower 



{Fig.) premolar, and a much-worn upper premolar ; from the 



Middle Eocene of Bracklesham, Sussex. The lower teeth 



are figured by Owen in the ' British Eossil Mammals and 



Birds/ p. 311, fig. 108. 



Bowerhank Collection. Purchased, 1865. 



26828. A lower premolar ; from the Middle Eocene of Argenton 

 (Indre), Erance. Pomel Collection. Purchased, 1851. 



Genus HYRACOTHERIUM, Owen 3 . 



Syn. Pliolophus, Owen 4 . 

 Orohippus, Marsh 5 . 



Dentition : — I. |, C. j, Pm. ~, M. |. The upper molars have low 

 crowns, with transverse ridges connecting the inner and outer 

 cusps, the anterior ridge being interrupted ; the ridges of the lower 

 molars are interrupted, and have a tendency to a crescentoid form ; 

 the first lower premolar is separated by an interval from the second. 

 The generic unity of Pliolophus with Hyracotherium is indicated by 

 Elower (Cat. Yert. Anim. Mus. Roy. Coll. Surg. pt. ii. Mammalia, 

 p. 380 [1884]), and that of the North- American Orohippus by Cope. 

 (Rep. U.S. Geogr. Surv. W. of 100th Meridian, Palaeontology, vol. iv. 

 pt. ii. p. 259 [1877]), both determinations being fully confirmed by 

 an examination of the specimens in the Museum. 



Hyracotherium leporinum, Owen 6 . 

 Syn. Pliolophus vulpiceps, Owen 7 . 



This is the type species. 

 Hah. Europe. 



1 Synopsis Mammalium, p. 413 (1829). 



2 Zool. et Pal. Franchises, 2nd ed. p. 126 (1859). 



3 Trans. Geol. Soc. ser. 2, vol. vi. pt. 1, p. 203 (1841, read 1839). 



4 Quart. Journ. Geol. Soc. vol. xiv. p. 54 (1857). 



5 Amer. Journ. ser. 3, vol. iv. p. 207 (1872). 



6 Trans. Geol. Soc. he. cit. 



7 Quart. Journ. Geol. Soc. loc. cit. 



