x ANIMAL LIFE 



CHAPTER IV 



MOVEMENT 



page 



A. The spectacle of movement 26 



1. Increasing finish of movement is accompanied by 

 elevation in the scale of being — Insects — Fish . . 26 



2. The finish and unweariedness of movement . . 27 

 ;. Its highest manifestation — The migration of animals 28 



B. Idle modes of animal motion — The analogy of a boat — 

 Leverage in swimming, walking, and flight — Other forms of 

 locomotion 



C. The movements of animalcules — Ciliary movement — Th 

 value of cilia — Movement essentially innate 



D. 1. The movement of worms and Crustacea .... ^7 

 2. Swimming, walking, and flight of insects .... 39 



E. The locomotion of vertebrates : 



r. Fish — Their methods of swimming — The use of the 

 tail and fins — Free swimming and ground fish — Attempts 

 at walking and flight 43 



2. Movement on land — Support and propulsion — 

 Movement and rest in an erect position — The changes 

 which have converted aquatic locomotor organs into ter- 

 restrial ones .......... 48 



3. Amphibia and Reptiles — Mammals — Running, climb- 

 ing and aquatic mammals — Whales and seals — Flving 

 mammals — Bats ......... ;o 



4. Birds — Their flight — Adaptation of the body — 

 Wings — Feathers — Methods of gliding and active flight — 

 Their adaptation for perching, running, and swimming — 



The structure of the legs and feet . . - 7 



CHAPTER A' 



THE QUEST FOR FOOD 



The source of animal food : the quest for plants : 



r. The need for food — Dependence of animal 011 plan! 

 life — The feeding of fixed animals — I he value of higher 

 plants to animals — Windfalls — Leaf mould. . 6" 



2. The feeding of Crustacea and insects — Their jaws, 

 lips, and tongues — The services ol insects to plants . . <>s 



