PREFACE. 



There is, perhaps, nothing about the science ol Zoology which 

 is so much a matter of individual opinion as the method of classiiica- 

 tion of the various animal forms ; and this is so in the nature of 

 things, since a classification is at best but an artificial arrangement for 

 convenience, and only in an incomplete and wholly inadequate way 

 represents the actual relationships. These difficulties have led many 

 teachers to practically disregard classification altogether ; but what is 

 thus gained in scientific accuracy is lost in clearness of arrangement, 

 and the whole study is apt to seem vague and uncertain. It is to pre- 

 vent this feeling of vagueness, and to furnish a foundation by means 

 of which the facts ascertained by the student may be arranged in 

 logical sequence, that I have attempted this outline, and in this 

 attempt I have sought to present a classification which is modern and 

 rests upon a morphological basis, but is, at the same time, one that is 

 dependent upon obvious points of structure, and is thus not too tech- 

 nical for the use of beginning students. 



In the artificial key at the end there is no attempt at morphological 

 grouping, and the characters emphasized are, as far as possible, the 

 most obvious ones. Its main value is that of an index by means of 

 which a student who investigates an animal for the first time may 

 guide himself to the proper part of the synopsis without being under 

 the necessity of applying to the instructor. 



Dryads' Green, 



Northampton, Mass., 



September, 1902, 



Ui 



