11 
INTRODUCTION. 
The Reptilia cannot, it must be acknowledged, offer such ostensible sources 
of amusement or interest as these : but to the philosophical student of Nature,— 
to him who seeks in his investigations for something beyond the mere gratifi¬ 
cation of the eye and ear, or the amusement to be derived from watching the 
changes of an insect, or the nidification of a bird,—to him, in short, who, in the 
expanded and almost boundless view of Nature which lies before him, endea¬ 
vours to trace something of the great plan on which this world of life has been 
organized, and to ascertain the very principles of that mighty and harmonious 
system, of which every variety of form, and every grade of organization con¬ 
stitutes an essential part,—no class of beings, however forbidding their outward 
appearance may be, or with whatever attributes of dread and disgust super¬ 
stition may have invested them, can be otherwise than interesting, and de¬ 
serving the most careful and profound investigation. 
It is obvious that in proportion to the extent of our acquaintance, not only 
with those types of form which indicate the centres of the different groups, 
but with the nicer gradations of structure which form the passage from one 
group to another, or the links by which they are associated, will be our means 
of advancing in the pursuit of this most important and interesting object, to 
which the anxious attention of every true naturalist has been directed, from 
Aristotle downwards to MacLeay. It is not that every species of a group— 
especially of some of the most extensive, and which contain numerous species 
of nearly the same form,—can be viewed as equally important: the decision, for 
instance, of every doubtful species of the Colubridse would be but a trifling 
and unimportant addition to our knowledge, with respect to the great object 
to which I have alluded; yet how often does it happen that an individual 
which, from superficial examination perhaps, or from the want of comparison, 
had been considered as isolated and bearing no near or important relation to 
any other form, proves, by the discovery of other intermediate species, or by 
further investigation of its own characters, to be the essential link in some 
important chain of affinity, or the analogical key to some corresponding form 
in another group. The distinct and certain settlement of disputed synonymy, 
too, cannot be considered as a very important object of the labours of the 
naturalist; yet even this, to an orderly and well-regulated mind, will be a source 
