PREFACE. ¥. 
in one case, of genera and families. This has been done 
partly because the same species is not always the most 
common one in different parts of New Zealand, but more 
especially to teach the student to attach a definite idea to 
the word species. Students should practice drawing, and 
writing descriptions of the different organs of the animals ; 
and the teacher will find that to make his pupils draw and 
describe what they see is the best method of examining 
them. 
The third part contains a summary of the characters of 
the principal groups of animals. Notwithstanding the tem- 
porary nature of all classifications 1t appears to me necessary, 
in order to fix the student?s ideas, that he should learn the 
characters of the principal groups. Without this he cannot 
understand the difference between the general structure of 
an organ throughout a group, and its actual structure in the 
species which he is examining, and there will be a want of 
mental perspective in the idea he forms of the animal king- 
dom. The references in this part to the literature of New 
Zealand animals are not intended to be complete, but all the 
more important papers are referred to, and the student will 
find in those that are mentioned references to others, and so 
will not be likely to overlook anything that has been 
published. 
I consider that exercises in the fourth part are of con- 
siderable importance in strengthening the powers of obser- 
vation, and in teaching accuracy. The process of deter- 
mining the group to which an organism belongs has, I think, 
