2 MAMMALIAN ANATOMY 



of development by descent through a line of other animals is termed 

 Phylogeny. 1 



When the anatomy of different animals is studied and their 

 homologous organs are compared, this study is known as Comparative 

 Anatomy. 



The classification of animals into larger and smaller groups is 

 studied under a subdivision of Morphology termed Taxonomy. 2 



The consideration of their life in the past, as shown from fossil 

 remains, constitutes the science of Palaeontology. 3 



Physiology, 4 in contrast to Morphology, which treats of the struc- 

 ture of living things, is the science which treats of the workings of 

 these structures, or their functions. For example, under Morphology 

 we study the structure of the lungs and their development, and 

 under Physiology we study the processes of breathing or respiration. 



Descriptive Mammalian Anatomy may be divided into two parts : 



The first part comprises the study of the microscopic structure of 

 tissues and of organs which constitute the body. This part is General 

 Anatomy, or Microscopic Anatomy, or Histology. 5 



The second part is Macroscopic, or Special Anatomy, and com- 

 prises the study of structures visible to the naked eye. 



Histology is studied by means of the microscope ; Special Anatomy 

 is studied by dissection, which is the cutting apart and disentangling 

 of the various structures. The study of animals by dissection is 

 sometimes called Zootomy.'' 



The most direct way of acquiring a knowledge of mammalian 

 morphology is by a thorough study of the anatomy of one mammal ; 

 the facts thereby gained show the general plan of structure, and 

 will serve as a basis for comparison with other animals. 



In our selection of the mammal as the subject of study we are 

 much restricted ; the requirements are exacting. It must be a familiar 

 animal, and readily obtained ; of convenient size, not too large to 

 handle easily, nor too small to make dissection difficult ; it must offer 



1 From (Gr.) phylon, stem, and genos. 



2 From (Gr.) taxis, orderly arrangement, and nemein, to distribute. 



3 From (Gr.) palaios, ancient, onta, beings, and logos. 

 * From (Gr.) physis, life, and logos. 



5 From (Gr.) histos, a tissue, and logos. 



6 From (Gr.) zoon, an animal, and temnein, to cut. 



