548 UNGULATES. 



Wild Boar, are compressed laterally with an elliptic transverse 

 section, and a smooth unenamelled exterior. Their socket seems 

 as if it had been pulled out or produced from the alveolar border 

 of the upper maxillary bone, and then bent abruptly upwards, giving 

 the tusk a direction upwards and backwards. The tooth pierces 

 the integuments of the upper lip, like a horn, and its growth, 

 being unchecked by any opposing tooth, sometimes forces the 

 tip again through the integument and into the substance of the 

 skull. The lower tusks have the ordinary direction, but rise rather 

 more vertically and much higher than in the Wild Boar ; they are 

 subtrihedral with rounded angles, except the inner one towards the 

 point, and sometimes show upon their inner side slight marks of 

 abrasion against the outer side of the base of the upper tusks. 

 These tusks are well adapted by their position to defend the eyes, 

 and assist in the act of forcing the head through the dense en- 

 tangled under-wood of a tropical forest, as suggested in Home's 

 Comparative Anatomy (Vol. i, p. 221) ; but their use has not 

 been determined by actual observation : speculation, however, has 

 not been idle in assigning final purposes to these singularly 

 developed teeth, which are too absurd for repetition. The molar 

 series is speedily reduced in the Babiroussa to two premolars and 

 three true molars on each side of both jaws : the great activity 

 of the vascular matrix of the long tusks soon exhausts the 

 conservative force of those of the adjoining small premolars. The 

 upper molars much resemble those of the Hog, but are relatively 

 narrower ; the four principal tubercles are better marked on the 

 penultimate and last true molars, and the accessory tubercular 

 talon of the latter is relatively smaller. In the lower jaw, also, 

 the third lobe of the last molar is smaller, and the four principal 

 tubercles constitute a more conspicuous and important part of the 

 crown. (1) 



(1) A fossil under jaw has been described and figured in Silliman's American Journal 

 of Science, Vol, xliii. 1842, PI. 3. fig. 1, under the name of Sus Americana, by Dr. Harlan, 

 •who conceived 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., although the Babiroussa 

 was a much smaller animal." Having compared a cast of this fossil jaw, I find that, besides 

 the diflference of size, there is a diflference in the proportions of the true molar teeth, the 



