338 ZOOLOGY 



scopes will, nevertheless, be able to select from nineteen exercises, 

 while those which in addition are unable to make use of living 

 marine animals will still have a choice from seventeen exercises. A 

 thorough study of a few types, rather than a more superficial study 

 of many, should be aimed at. 



General aim. - - It is the general aim of these exercises to interest 

 as well as to train the pupil ; indeed, it is believed that the awakening 

 of interest is the best preliminary and accompaniment to a useful 

 mental training. Since young persons are especially interested in 

 living animals, observations and non-injurious experiments upon the 

 normal reactions and the methods of locomotion of animals are 

 required in nearly every exercise. While the study of active animals 

 will entail much additional labor on the part of the teacher, and 

 some additional expense, it is believed that the results will justify 

 the cost. In order to carry out the aim of these exercises, it is desir- 

 able that the student find answers to his questions, as far as practi- 

 cable, from the object before him, rather than from the teacher or 

 from books. Questions involving comparisons between the types have 

 been omitted, not because they are regarded as unimportant, but 

 because they would necessarily vary according to the particular 

 types selected and the order in which these types are studied. How- 

 ever, the necessity which compels their omission is the less to be 

 regretted, since it leaves the teacher free to exercise his ow r n judg- 

 ment and experience in this matter, but he should not fail to supply 

 such questions. 



Sequence of exercises. The sequence of exercises must depend 

 largely upon availability of material ; but it is desirable that closely 

 related types should be studied in immediate succession to facilitate 

 comparisons. The following are suggested for courses occupying 

 different periods in the year : 



