aK SO Mal nstityys 
STEJNEGER 7 
COLLECTION 
Nations) Muses 
PREFACE. 
Tue distinctive character of this work consists in the 
treatment of the whole Animal Kingdom as a unit; in 
the comparative study of the development and variations 
of organs and their functions, from the simplest to the 
most complex state; in withholding Systematic Zoology 
until the student has mastered those structural affinities 
upon which true classification is founded; and in being 
fitted for High Schools and Mixed Schools by its language 
and illustrations, yet going far enough to constitute a com- 
plete grammar of the science for the under-graduate course 
of any College. 
it is designed solely as a manual for instruction. It is 
not a work of reference, nor a treatise. So far as a book 
is encyclopediac, it is unfit for a text-book. This is pre- 
pared on the principle of “just enough, and no more.” It 
aims to present clearly, and in a somewhat new form, the 
established facts and principles of Zoology. All theoretical 
and debatable points, and every fact or statement, however 
valuable, which is not absolutely necessary to a clear and 
adequate conception of the leading principles, are omitted. 
It is written in the light of the most recent phase of the 
science, but not in the interest of any particular theory. 
To have given an exhaustive survey of animal life would 
not only have been undesirable, but impossible. Even 
Cuvier’s great work must be supplemented by museums, 
