x PREFACE. 
so far as is necessary to give completeness to the externals of 
the animals studied. In a utilitarian view the branch of the sub- 
ject which I have examined may be of the most interest ; but for 
strictly scientific research the others are not less important, for 
all must be exhausted before the natural history of an animal is 
understood. 
By limiting myself to a few species, it has been possible for me 
to descend to greater detail, in describing my animals, than was 
possible to those who have gone before me, who have embraced 
in their investigation a large portion of the animal kingdom, and 
could afford to each species but a limited space. I appreciate 
that I have burdened the text with a great accumulation of facts, 
but I have been careful that they should be well attested. I 
have omitted many observations from fear of prolixity. 
It is not to be denied that zodlogy, especially when treating 
of the larger animals, man alone excepted, has been the subject 
of less careful study than many, if not most, of the other natural 
sciences. From the great extent of the field it is impossible for 
any one man to explore originally the whole or any considerable 
part of it, except in the most general way. It has been impos- 
sible for any of our great naturalists to descend to that minute- 
ness in their investigations which characterizes the students of 
some other branches of science. Let us admire the painstaking 
archeologist who overlooks nothing which can throw a ray of 
light upon the subject of his inquiry. A chip from a flint imple- 
ment; an impress upon a piece of pottery; a hole in a pebble; a 
scratch on a fragment of bone, —all are noticed, recorded, pon- 
dered, and compared with others, brought perhaps from a distant 
part of the world, until that which was dark and unmeaning be- 
comes light and instructive. So by patience and perseverance the 
student learns how to observe those letters of antiquity, to com- 
prehend their value and significance, and to combine them into 
words and sentences and discourses, while those who have not 
thus trained themselves can see nothing but chips and fragments | 
and scratches. 
