CHAPTER XXIV. 



CLASS V. MAMMALIA (MAMMALS). 



434. Laboratory and Field Work. Almost any of the 

 smaller mammals may be used in the following exercise. Dif- 

 ferent species may be taken with profit by the various mem- 

 bers of a class. The chief points to be emphasized are the 

 habits, instincts and external structure. 



I. Habits and Instincts. 



What are its natural haunts? What explanation can you 

 offer therefor ? 



How does it protect itself from its enemies? What are its 

 enemies ? Is it active at night or by day ? Reasons ? 



What are its habits as regards food ? Evidences ? 



What can you say of its power and manner of locomotion? 

 Does the manner of motion differ materially with differ- 

 ence of rate? 



Social habits? Mating habits? Care of young and their 

 condition at birth ? 



Is it scarce or abundant ? Apparent reasons ? 



What are its relations to human interests ? 



II. General Form and Structure. 



Identify the regions of the body and compare the condition 

 found here with that seen in the birds. Relation of axis 

 of body to appendages. Compare the anterior and pos- 

 terior appendages at all possible points, and show to 

 what extent the work done by each is indicated by the 

 structure. Examine the claws and the soles of the feet. 



Examine the body-covering, and compare the various parts 

 as to color, character of hair, etc. Does the hair com- 

 pletely cover the body? What is the position and use of 

 " whiskers " ? Evidences for your conclusion. 



Locate all the external openings. Study the mouth with its 



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