ELEMENTS 



OF 



MAMMALIAN ANATOMY. 



INTRODUCTION. 



Since this book is designed for the use not only of 

 students who have pursued the study of biology for some 

 time, but also for those making their first actual acquaint- 

 ance with the subject, it may be well to call attention to 

 the fact that any animal or plant may be considered from 

 several different standpoints. A general study of structure 

 and of the relations of the various systems and organs is 

 known as Anatomy. Histology concerns itself with the 

 cell and cell aggregates or tissues composing the organs. 

 These two sciences are included in Morphology, a term 

 which by many is made to include also Embryology or 

 Ontogeny, treating of the development of an organism from 

 the egg, or its vegetable homologue, to the period of assum- 

 ing adult characteristics. Since ontogeny deals not only 

 with the growth of structure but also the process of growth, 

 it may likewise be included under Physiology, a science 

 which has for its province the investigation of the functions 

 of the organs and systems. A special field of physiology 

 having for its consideration the operations, especially the 

 conscious operations of the nervous system, constitutes the 

 science of Psychology. 



The same species of animals are not found in all parts 

 of the world. The lion and tiger are found wild only in 



