'2X2 



ZOOLOGY, 



mous weight of the head renders a probi<-U iirrrs>arv t<> tin- 

 existence of tlic animal, without which it could neither leni 

 nor drink. 



Fig. 179. Head of the Tapir. 



Fig. 180. The L>.-MU;IH. 



The elephants are the only animals which have a proboscis, 

 but there are others in which the nasal organs are prolonged 

 into something analogous. Such are the tapirs (Fig. 179). 

 The desmans (Fig. 180), small insectivorous animals, allied 

 to the musaraignes, but adapted for swimming with rase. 

 and searching for their food at the bottom of burrows dug in 

 beaches, present a similar elongation of the nostrils. 



395. The Trunk. The vertebral column presents but 

 slight modifications in the vertebrata, and these are chiefly 

 confined to a difference in the number of the vertebra). 

 Again, this difference is chiefly remarkable in the caudal or 

 i-nccygeal part of the column; in some, as in bats of the 

 genus roussette, there exist no coccygeal vertebra' whatever ; 

 in other mammals, they number forty, fifty, and even sixty ; 

 and in these we also find this distinction, that the vertebral 

 canal for lodging the spinal marrow and a portion of its 

 nerves, still exists in some of these bones, whilst in the termi- 

 nating ones it is wholly absent. In most mammals the caudal 

 part of the column is but little used for locomotion : in the 

 kangaroo, jerboa, &c., it becomes, with the hinder limbs, a sort 

 of tripod, from which the animal springs with great force 

 (Fig. 87) ; many American apes use the tail as a prehensile 

 organ of great power, as a fifth hand in fact, by which they 

 dexterously cling to branches of trees (Fig. 93); finally, in the 

 crtarra it becomes enormous, and serves as their 

 moving agent in swimming. It is beneath the bodies of 

 these caudal vertebrae that we find the bones shaped like 

 the letter V, which seem to serve as ribs to strengthen the 

 flexor muscles of the tail (Fig. 181). The length of the neck 

 varies also in mammals, although the number of cervical 



