316 ZOOLOGY 



to note that America was the original home of the horse. Ages 

 ago, the ancestor of the present horse was not larger than a fox 

 terrier, and instead of having one toe prolonged into a hoof, it 

 walked on five toes. Later changes probably caused the little 

 horse to abandon the life it led in the swamp for that on drier 

 land. At that time it v*^as about the size of a sheep and had 

 three toes in each foot. Later the longer-legged and single-toed 

 horses probably became speedier, thus escaping from the numerous 

 carnivores which must have preyed upon them. So ultimately 

 by very gradual variation the present horse was evolved. This 

 purely hypothetical history was probably repeated with variations 

 in the case of many other species of animals. 



Man^s Place in Nature. — Although we know that man is sepa- 

 rated mentally by a wide gap from all other animals, in our study 

 of physiology we must ask where we are to place man. If we 

 attempt to classify man, we see at once he must be placed with 

 the vertebrate animals because of his possession of a vertebral 

 column. Evidently too, he is a mammal, because the 3^oung are 

 nourished by milk secreted by the mother and because his body 

 has at least a partial covering of hair. Anatomically we find that 

 we must place man with the apelike mammals, because of these 

 numerous points of structural likeness. The group of mammals 

 which includes the monkeys, apes, and man we call the primates. 



Reference Books 

 for the pupil 



Davison, Practical Zoology, pages 261-292. American Book Company. 

 Herrick, Text-hook in General Zoology, Chap. XXIV. American Book Company 

 Ingersoll, Wild Neighbors. The Macmillan Company. 

 Ingersoll, Life of the Mammals. The Macmillan Company. 



FOR THE TEACHER 



Dodge, General Zoology, pages 177-202. American Book Company. 

 Riverside Natural History. Houghton, Mifflin, and Company. 



