224 



FIRST YEAR SCIENCE 



any other domestic animal. Some of these should be read for 

 further information concerning this most instructive animal. 



105. Vertebrates. Experiment 115. If possible, secure the 

 skeleton of some vertebrate animal, preferably man. Notice how the 

 bones are fitted to each other and how the joints are arranged to allow 

 movement. Observe how carefully the brain and the spinal cord are 

 protected, and also the thorax, which contains the heart and lungs. 

 If a human skeleton is procured, notice the curving of the spine 

 which enables the body to stand erect. 



We have just studied briefly some of the invertebrates 

 most closely related to the welfare or injury of man. Man 

 himself belongs to the other great class, 

 vertebrates. The higher animals which 

 furnish him with the greater part of 

 his animal food also belong to this 

 class. Although there are great vari- 

 ations in the structure of vertebrate 

 animals, yet they are alike in having 

 a backbone and an inner supporting 

 skeleton. 



The bony skeleton in the higher forms 

 of animal life consists of a vertebral 

 column, skull, ribs and appendages. 

 The main skeleton protects the most 

 delicate organs and acts as a support 

 for the attachment of the muscles. The 

 appendages, like the legs and arms in 

 A HUMAN SKELETON, man, are jointed to the central part 

 of the skeleton, and it is the action of 

 the muscles in moving these about the 

 joints that makes movement from place 

 to place possible. 



In the skull is situated the great nerve center of the 

 animal, the brain, and from this through the vertebral 



Notice how the bones 

 are arranged to pro- 

 tect the delicate or- 

 gans. 



