MAIN PATHWAYS AND TENDENCIES 107 



eye view with brief comments will help mark the 

 pathways of the territory. 



Structural Zoology. The two broad aspects in the 

 investigation of animal forms are morphological and 

 physiological. Supplemental to one another, they 

 embrace the statics and the dynamics of animals 

 the architecture and the function. Structural 

 zoology (or morphology) is fundamental in providing 

 a basis for physiological investigations. It includes 

 topics dealing with gross and minute anatomy, with 

 the process of building, or development of the body, 

 and the study of fossil animals. Accordingly, we 

 recognize its chief subdivisions as comparative 

 anatomy, histology, embryology and paleontology 

 (paleozoology). 



Comparative Anatomy. The study, broadly com- 

 parative, of the structure of animals, well adapted for 

 the early stages of laboratory observation, usually 

 pursued by an examination of types of animal life 

 from the lowest to the highest. The microscope is 

 necessary for the examination of the whole group of 

 protozoa and for other minute animals such as 

 rotifers, microscopic Crustacea, etc. 



Comparative anatomy is chiefly the structural 

 study of animals as to their organs and systems of 



