irrels of many kinds were kept in numbers, but Mr.
Thompson, the superintendent, told me that none had ever bred there, or
elsewhere as far as he knew. I have never heard of the English squirrel
breeding in confinement. But the species which has bred more than once
in the Zoological Gardens is the one which perhaps might have been
least expected, namely, the flying squirrel (_Sciuropterus volucella_):
it has, also, bred several times {153} near Birmingham; but the female
never produced more than two young at a birth, whereas in its native
American home she bears from three to six young.[344]

Monkeys, in the nine-year Report from the Zoological Gardens, are
stated to unite most freely, but during this period, though many
individuals were kept, there were only seven births. I have heard of
one American monkey alone, the Ouistiti, breeding in Europe.[345] A
Macacus, according to Flourens, bred in Paris; and more than one
species of this genus has produced young in London, especially the
_Macacus rhesus_, which everywhere shows a special capacity to breed
under confinement. Hybrids have been produced both in Paris and London
from this same genus. The Arabian baboon, or _Cynocephalus
hamadryas_,[346] and a Cercopithecus have bred in the Zoological
Gardens, and the latter species at the Duke of Northumberland's.
Several members of the family of Lemurs have produced hybrids in the
Zoological Gardens. It is much more remarkable that monkeys very rarely
breed when confined in their native country; thus the Cay (_Cebus
azarae_) is frequently and completely tamed in Paraguay, but
Rengger[347] says that it breeds so rarely, that he never saw more than
two females which had produced young. A similar observation has been
made with respect to the monkeys which are frequently tamed by the
aborigines in Brazil.[348] In the region of the Amazons, these animals
are so often kept in a tame state, that Mr. Bates in walking through
the streets of Para counted thirteen species; but, as he asserts, they
have never been known to breed in captivity.[349]

_Birds._

Birds offer in some respects better evidence than quadrupeds, from
their breeding more rapidly and being kept in greater numbers. We have
seen that carnivorous animals are more fertile under confinement than
most other mammals. The reverse holds goo