24 ELEMENTS OF MAMMALIAN ANATOMY 



bladder. It must be remembered that the material known as 

 feces passed out of the alimentary canal through the anus is not 

 an excretion of the cells of the body, but largely that portion of 

 the food not transformed into a condition permitting it to be 

 absorbed by the villi. 



In addition to these systems necessary for the maintenance 

 of life, the cat requires a means for supporting the body and 

 moving about, furnished by the osseous and muscular systems. 

 The osseous system serves not only for support and locomotion, 

 but also for the protection of the. delicate vital organs. The 

 skull and spinal column contain the brain and spinal cord, while 

 the heart and lungs are well shielded by the dorsal vertebrae, 

 the ribs, and sternum. Likewise the muscles ward off serious 

 injuries from the blood-vessels, as they cover to a considerable 

 depth nearly all large arteries, and also aid by their contraction 

 in moving the lymph through the numerous lymphatic vessels 

 extending from the extremities to the jugular veins. 



These systems previously described are capable of per- 

 forming their functions only when supplied with nerves through 

 which impulses can be transmitted from the brain and spinal 

 cord. 



The only system which is not absolutely necessary to the life 

 of the cat is the reproductive; but this is required for the con- 

 tinuance of the species. It is not, however, functional during 

 the entire life, but as a rule only from the end of the first to 

 the tenth year. 



LABORATORY STUDIES AND SUGGESTIONS 



1. What advantages are derived from the study of mammalian anatomy? 



2. Define morphology and state a fact from that science. 



3. What two sciences does biology include? 



4. What five sciences are included in zoology? 



5. Make a physiologic statement concerning the heart. 



6. State five facts belonging to the science of distribution. 



7. What is taxonomy? 



8. Name five classes of vertebrates. 



9. By examining specimens discover what external feature distinguishes a 

 reptile from an amphibian. 



