PROF. OWEN ON CERTAIN FOSSIL BONES. 19 



tinguishes this tooth in the Lophiodon from that of the Tapir. The teeth of the fossil 

 from Georgia a little exceed in size those of the Lophiodon Isselanus {Grand Lophiodon 

 d'Issel, Cuvier, ' Ossemens Fossiles,' ed. 1822, torn. 2, pt. 1, p. 184, pi. 3, fig. 3,) the 

 antero-posterior diameter of the last molar in that species being one inch and eight 

 lines, and in the present fossil one inch ten lines. But the depth of the jaw below 

 the middle of the last molar in the pi-esent fossil is three inches ; whilst that in the 

 Lophiodon Isselanus in the figure cited, is scarcely two inches; and Cuvier expressly 

 states (p. 186) that it surpasses in depth the corresponding part of the jaw of the 

 Lophiodon medius (pi. 3, fig. 1,) which has molar teeth of the same size as in the 

 Lophiodon Isselanus. 



The present fossil has been described and figured in " Silliman's American Journal 

 of Science," vol. 43, 1842, pi. 3, fig. 1, under the name of Sus Americana; Dr. Harlan 

 conceiving that from its general appearance and number of the teeth this fragment 

 bore a close analogy with the same part in the Sus babirussa, Buff., acknowledging, 

 however, that the Babyroussa " was a much smaller animal." Besides the difference 

 of size, the last molar in the fossil has the anterior transverse ridge proportionally 

 larger, and the posterior lobe proportionally smaller than in the Babyroussa, resem- 

 blino- the Lophiodon in the points in which it thus differs from the species of Sus cited. 

 The form of the fossil jaw differs at the part supporting the last molar from that in 

 the Babyroussa, where the socket of the last molar overhangs the inner surface of the 

 ramus, whilst in the fossil the inner surface of the ramus beneath the last molar 

 describes a gentle convexity from the tooth to the lower margin of the ramus. The 

 outer part of the ramus of the jaw of the Babyroussa begins to expand below the 

 fourth and fifth molars, counting forwards from the last, to form the socket of the 

 large tusk ; but the fossil jaw does not offer the least indication of an enlargement 

 for that purpose; and the fractured anterior end, as displayed in the cast, is very 

 different in shape from the corresponding part of the jaw in the Babyroussa, and 

 shows merely the wide dental canal, and no socket for the tusk which would be here 

 situated in the Babyroussa or Wild Boar. 



The nearest approximation which I could make from a study of a cast of the fossil 

 in question to any known existing or extinct animal, was to the great tapiroid Pachy- 

 derms; but I added in my description of this cast in the " Catalogue of Fossil Mam- 

 malia and Birds in the College of Surgeons," 4to., 1845, p. 198, "that ulterior dis- 

 coveries, may, indeed, show that the Lophiodont dentition was combined with other 

 characters in the American fossil, necessitating a generic distinction, and it is well to 

 remember that the dentition of the Macranchenia, of South America, a three-toed 

 Pachyderm with an astragalus almost identical with that of the Lophiodon, and of a 

 size which agrees with the jaw of the fossil Sus Americana of Harlan, has yet to be 

 discovered." 



The orio-inal of the cast shows the course of the enamel on the outer side of the 



