104 COMPAIUSOKS OF STKUCTUUE IN ANIMALS. 



trunk and a liiige head, while the weight of 

 the latter, increased by heavy tusks, necessi- 

 tates the abbreviation of the neck, which, if 

 elongated, vrould give way beneath the load to 

 be sustained. This shortness of neck prevents 

 the elephant either from depressing its head to 

 cake food on the around, or from raising it, to 

 browse on the leaves of trees. It requires an 

 arm, and it has one : this arm is its trunk, or 

 proboscis, at once an organ of touph, and an 

 instrument of prehension. When we apply the 

 term arm to the proboscis of the elephant, we 

 do so in a figurative sense merely, for, strictly 

 speaking, it is only a modification of the snout, 

 or nasal termination carried to a very high 

 degree, so as to constitute an available instru- 

 ment, the consideration of w^hich is very in- 

 teresting. This proboscis consists of two 

 canals, beginning at the nasal cavity of the 

 skuU, and divided from each other by a 

 tendinous partition. Externally, it presents 

 the form of an elongated cone, convex anteriorly 

 and flattened posteriorly, the flattened portion 

 having a rough projecting margin on each 

 side at its junction with the convex, continued 

 throughout its whole length. The anterior 

 surface is furro-\ved by numerous transverse 



