HUXLEY, ON CLASSIFICATION. 65 
to speak of a classification than of the classification of the animal 
kingdom, 
The preparations in the galleries of the Museum of this College 
are arranged upon the basis laid down by John Hunter, whose 
original collection was intended to illustrate the modifications which 
the great physiological apparatuses undergo in the animal series: 
the classification which he adopted is a classification by organs, and, 
as such, it is admirably adapted to the needs of the comparative 
physiologist. ; 
But the student of the geographical distribution of animals, 
regarding animated creatures, not as diverse modifications of the 
great physiological mechanism, but in relation to one another, to 
plants and to telluric conditions, would, with equal propriety, dispose 
of the contents of a Zoological Museum in a totally different manner ; 
basing his classification, not upon organs, but on distributional 
assemblages. And the pure palxontologist, looking at life from yet 
another distinct point of view, would associate animal remains 
together on neither of these principles, but would group them accor- 
ding to the order of their succession in Time. 
Again, that classification which I propose to discuss in the present 
Lectures, is different from all of these: it is meant to subserve the 
comprehension and recollection of the facts of animal structure; and, 
as such, it is based upon purely structural considerations, and may 
be designated a Morphological Classification. I shall have to consider 
animals, not as physiological apparatuses merely ; not as related to 
other forms of life and to climatal conditions; not as successive 
tenants of the earth; but as fabrics, each of which is built upon a 
certain plan. 
It is possible and conceivable that every animal should have been 
constructed upon a plan of its own, having no resemblance whatsoever 
to the plan of any other animal. For any reason we can discover to 
the contrary, that combination of natural forces which we term Life 
might have resulted from, or been manifested by, a series of infinitely 
diverse structures: nor, indeed, would anything in the nature of the 
case lead us to suspect a community of organization between animals 
so different in habit and in appearance as a porpoise and a gazelle, 
an eagle and a crocodile, or a butterfly and a lobster. Had animals 
been thus independently organized, each working out its life by a 
mechanism peculiar to itself, such a classification as that which is 
now under contemplation would obviously be impossible; a morpho- 
logical, or structural, classification plainly implying morphological, 
or structural, resemblances in the things classified. 
As a matter of fact, however, no such mutual independence of 
animal forms exists in nature. On the contrary, the different. mem: 
