clinging together. They collect food for the community, and when an
object, too large for entrance, is brought to the nest, they enlarge
the door, and afterwards build it up again. They store up seeds, of
which they prevent the germination, and which, if damp, are brought up
to the surface to dry. They keep aphides and other insects as
milch-cows. They go out to battle in regular bands, and freely
sacrifice their lives for the common weal. They emigrate according to a
preconcerted plan. They capture slaves. They move the eggs of their
aphides, as well as their own eggs and cocoons, into warm parts of the
nest, in order that they may be quickly hatched; and endless similar
facts could be given. (2. Some of the most interesting facts ever
published on the habits of ants are given by Mr. Belt, in his
Naturalist in Nicaragua, 1874. See also Mr. Moggridge s admirable
work, Harvesting Ants, etc., 1873, also L Instinct chez les
Insectes, by M. George Pouchet, Revue des Deux Mondes, Feb. 1870, p.
682.) On the whole, the difference in mental power between an ant and a
coccus is immense; yet no one has ever dreamed of placing these insects
in distinct classes, much less in distinct kingdoms. No doubt the
difference is bridged over by other insects; and this is not the case
with man and the higher apes. But we have every reason to believe that
the breaks in the series are simply the results of many forms having
become extinct.
Professor Owen, relying chiefly on the structure of the brain, has
divided the mammalian series into four sub-classes. One of these he
devotes to man; in another he places both the marsupials and the
Monotremata; so that he makes man as distinct from all other mammals as
are these two latter groups conjoined. This view has not been accepted,
as far as I am aware, by any naturalist capable of forming an
independent judgment, and therefore need not here be further
considered.
We can understand why a classification founded on any single character
or organ even an organ so wonderfully complex and important as the
brain or on the high development of the mental faculties, is almost
sure to prove unsatisfactory. This principle has indeed been tried with
hymenopterous insects; but when thus classed by their habits or
instincts, the arrangement proved thoroughly artificial. (3. Westwood,
Modern Classification of Insects, vol. ii. 1840, p. 87.)
Classifications may, of course, be based on any character whatever, as
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