MAMMALS 337 



cious mouth with which it takes up great quantities of sea 

 water containing countless numbers of small animals. It 

 would be unpleasant and not economical to swallow such 

 mouthfuls of sea water. Consequently, in place of the teeth, 

 there grow these filaments of whalebone from the upper 

 jaw that act as a strainer in allowing the water to escape, 

 retaining the myriads of small animals for food. 



An elephant's trunk is wonderfully well adapted to the 

 needs of that animal. The great tusks prevent the animal 

 from reaching the ground with its mouth to pick up food ; 

 but the trunk with its innumerable muscles forms a grasp- 

 ing organ of wonderful delicacy and flexibility with which 

 anything from hay to peanuts or bits of candy may be 

 conveyed to the mouth. 



The members of the cat family catch their prey by 

 slipping up and pouncing upon it unawares. For holding 

 their prey securely the toes are provided with very sharp, 

 hooked claws. However efficient and necessary these claws 

 are, they would nevertheless be of very great inconvenience 

 were they prominently protruding from the feet. The 

 claws would catch in various objects, causing noise, stum- 

 bling, and all sorts of annoyances. To avoid this, they can 

 be retracted into the folds of the skin and hair, where they 

 cannot cause unexpected trouble ; and at the same time this 

 retraction makes possible the still, noiseless tread so char- 

 acteristic of cats. 



If the whales stand first as showing the most remarkable 

 modifications of structure to suit their environments, then 

 the bats ought to stand very close to them. It is very 

 remarkable that a mammal clothed with hair and without 

 feathers should still be capable of very perfect flight. 

 Moreover, the bats fly in the night time and do not have 

 hebrick's zooi,. — 22 



