Classification of Animals, 557 
or can be detected in the great groups of nature. The definitions, 
therefore, that have been given of the distinctive characters of a ve- 
getable and an animal, can only relate to the differences between 
the typical forms of each. " On this head," Mr Swainson observes, 
" we can add nothing to the definitions given by Linnaeus, Cuvier, &c. 
or to the acute reasonings of Mr M'Leay, premising only, that the 
value of every character that can possibly be devised, will progres- 
sively be deteriorated, and finally lost, as we recede from the circle 
of vertebrated animals, and approach the confines of the vegetable 
kingdom." After giving a tabular view of the probable number of 
existing species of animals, which he calculates at near 600,000, an 
estimate we believe below, rather than above, the actual amount, he 
indulges in the following reflections, which are so appropriate, that we 
make no apology for quoting them at length. " It is then, with such 
vast hosts of diversified beings that the naturalist has to treat. These 
are his materials of study and contemplation, and these he is to ex- 
amine, and, in some measure, to understand, before he can obtain a 
glimpse of the plan upon which they have been created. But, how- 
ever overwhelming to the mind this number, viewed abstractedly, 
may appear, it loses much of its formidable character, when we per- 
ceive that nature herself has divided and subdivided it into larger 
and smaller assemblages ; and that through all, and between all, 
there is a degree of order and of harmony which enables the mind to 
contemplate and investigate one portion, without the absolute neces- 
sity of grasping at the universal knowledge of all. This order and 
consistency in the creation, is productive of another advantage : it 
not only enables us to form correct notions on the leading peculiari- 
ties of large groups, without venturing upon the Herculean, or ra- 
ther endless task of analysing the properties of every species, but it 
likewise gives us the power of forming just comparisons, by contrast- 
ing any one of these groups with others." Again, " the truth seems 
to be, that the primary types of nature are very few, but that the va- 
riation of these types sometimes appears to be all but infinite. Thus 
no one can mistake a bird for a quadruped, or this again for a fish ; 
one individual from each of these classes is quite sufficient to give us 
a correct and definite idea of the rest ; and yet we have reason to be- 
lieve, that the form of a bird can be varied without the least depar- 
ture from its characteristic structure in more than six thousand dif- 
ferent ways ! The typical form of a fish admits probably of eight 
thousand variations. But these are nothing when we come to an- 
nulose animals. The most ordinary observer, if he sees a " creeping 
