August, 1846.] 95 



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 be- 

 low 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 Baby- 

 roussa, 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 Pachyderms ; but I added in 

 my description of this cast in the Catalogue of Fossil Mamma- 

 lia and Birds in the College of Surgeons 4to. 1845, p. 198, " that 

 ulterior discoveries, may, indeed, show that the Lophiodont denti- 

 tion 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 original of the cast shows the course of the enamel on the 

 outer side of the penultimate molar ; it there defines an anterior 

 lobe of the crown about one-third the antero-posterior extent of 

 the crown, by a close, straight fold of enamel penetrating inwards 

 about 2J lines. 



The anterior lobe or transverse ridge of the corresponding tooth 

 of a Lophiodon might, perhaps, present a similar appearance, if 

 worn down to the base of the crown. 



But in the present fossil, the enamel proceeds to define a mid- 

 dle lobe on the outer side of the crown, shorter than the foregoing, 

 beyond which the enamel and dentine are worn obliquely away 

 to the base of the posterior fang ; the indication of the middle ex- 



