IV 
INTRODUCTION. 
This variety of structure also is effected by sim- 
ply varying the primitive type of the parts, which 
are thus made capable of fulfilling a vast variety 
of intentions, according to the residence of the 
creatures within or on the earth, the sea or air : 
whilst the gradations of form and intellect in the 
different classes, with the evident analogies of 
at least many of the races to each order, and 
✓•the light which the variety of structure in the 
organs of the higher animals is calculated to 
throw on the functions of correspondent parts 
in the human body, are all matters of deep 
philosophic interest ; and whilst they show that 
the creative power of nature is one, claim for 
the study of his works a place amidst the highest 
branches of science. 
For the same reason that the subject is gene- 
rally interesting, that part of it which relates to 
the creatures of our own country must be more 
especially so ; and it is only when our curiosity 
in this respect is in some degree satisfied, that 
we direct a minute attention to those of distant 
countries. 
And this indeed must be considered as the 
proper course of study, even with those who 
seek the most extended information, or who 
desire to add by discovery to our present stock 
of knowledge. With regard to the former, the 
structure, peculiarities and habits of life, of the 
creatures of our own neighbourhood, will serve 
as the best foundation on which to build the edi- 
fice of general learning, and as subjects of com- 
parison by which we are able more readily to 
understand the description and history of those 
of which the accounts reach us only in books; 
and for the latter, many who have no opportunity 
of pursuing enquiries in distant regions, may still 
be able to notice things that have been overlook- 
ed by others ; and so far at least, is the science 
