ISO ON THE FOSSIL BONES OK TACHYDERMATOUS QUADRUPEDS. 



SECTION I. 



OV LIVING ELEPHANTS. 



The genus of the elephant is one of the most extraordinary in the 

 entire animal kingdom ; its structure is such, that it does not com- 

 pletely approach any other ; and though naturalists may have classed 

 it among the pachydermata, \vitli the rhinoceros, hippopotamus, and the 

 hog, it differs much more from all these quadrupeds than they differ 

 from each other; We may even say that in several respects this gigan- 

 tic animal presents striking traits of resemblance with the order of the 

 glires, which of all the orders of mammifera is most restricted in size. 

 Let us, in fact, compare successively all the parts of the head of the 

 elephant with that of the other animals, it is almost always among the 

 glires that we shall find their analogies. 



The enormous alveoli of the incisors are the first and most striking 

 of the characters which ai'e common to them. 



The size of the sub-orbital foramen is a second. It is only in some 

 glires, particularly of the tribe which are without clavicles, and whose 

 nails are nearly as developed as hoofs, in the cabiais, pacas, and por- 

 cupines, that we see suborbital foramina equalling or surpassing that of 

 the elephant : and the reason of it is that these animals require, for 

 their enormous muzzle, considerable nerves; which is necessary also 

 for the trunk of the elephant. 



The zygomatic arch is strait, and again formed in the elephant as 

 in these glires; the osjugale is, in each, suspended in the centre of the 

 arch. 



The length of the upper incisors, that is to say of the tusks, which 

 correspond to the incisors of other quadrupeds, by their insertion into 

 what is called the incisive, or intermaxillary bone, is a characteristic 

 owing in a manner to that of the size of their alveoli. In fact, the 

 name of incisors is not applicable to the tusks of the elephant, which 

 grow indefinitely, and are not at all trenchant; but their growth 

 arises from this circumstance, that they are not arrested by encounter- 

 ing the lower teeth, and their want of cutting power is to be at- 

 tributed to their enamel enveloping them equally on every side. 

 These two circumstances, which assign to tusks a different use from 

 that of ordhiary incisors, take nothing from the analogy in nature and 

 position of these two sorts of teeth ; we even know that in the true 

 glires, when an incisor falls by accident, the ojiposite incisor is pro- 

 longed nearly as much in proportion as the tusks of the elephant, but 

 in an irregular direction, Avhich sometimes even causes the death of 

 the animal, by preventing it from takins: its food. The tusks, which 

 were not destined, as the incisors of glires, for the division of aliments, 

 either of wood or bark, have not received on their anterior surface 

 that layer of a thick and hard enamel, which, by means as simple as 

 efficacious, keeps the incisors of glires always sharp ; they even have 

 an enamel so tender, that without the diflferent direction of its fibres, 

 one might confound it with ivory. 



