UNGULATA. 287 



similar to that of the existing pangolins (Mania) of Africa and 

 Asia, and other more uncertain limb-bones perhaps of the same 

 type occur in the same formation. The fronto-nasal region of a 

 small narrow skull (Leptomanis edwardsi) has also been found 

 here, and may be referred with even more probability to an 

 extinct pangolin. Another humerus (named Paheorycteropus 

 quercyi) from the same Phosphorites, much resembles the 

 corresponding bone of the' living aard-vark (Orycteropus) of 

 Africa ; and the last-mentioned animal itself is known to have 

 had a much wider distribution in Pliocene times than at 

 present, a typical skull being known from the Island of Samos 

 in the Turkish archipelago, and a detached tooth from Maragba 

 in Persia. 



ORDER 4. UNGULATA. 



In the earliest Eocene strata of North America, from which 

 numerous nearly complete skeletons have been obtained, it is 

 almost impossible to distinguish the forerunners of the herbi- 

 vorous mammals with hoofs (Ungulata) from those of the 

 carnivorous mammals with claws (Unguiculata = Carnivora, etc.). 

 Both are small plantigrade five-toed animals, with terminal 

 phalanges which are usually not quite in the form either of 

 claws or of hoofs, and with a mobile fore limb ; while both have 

 more or less tubercular molars and premolars, the tubercles in 

 the one case being only less pointed or cutting than in the 

 other. The typical Ungulata, however, soon become differen- 

 tiated, and before the close of the Eocene period, both in North 

 America and Europe, they have already begun to diverge into 

 the principal sub-ordinal groups. 



As this course of evolution is traced upwards through the 

 Tertiary formations, the changes in the skeleton are all much 

 of the same type. In general terms, they relate to the modi- 

 fication of small marsh-dwelling or forest-dwelling animals, 

 which were adapted to live on succulent vegetation, into hard- 

 hoofed quadrupeds more fitted for life on grassy plains and 

 with powerful grinding teeth capable of masticating compara- 

 tively coarse and dry herbage. The theory is indeed often 

 advanced, that the whole of this development of the Ungulata 



