NESTS. 
173 
more especially tlie parrots, are well-known to be sus- 
ceptible of these sorts of acquirements ; the superiority 
of the latter, in this respect, can be traced to the pre- 
eminent docility which characterises the Rasorial type of 
nature, whether seen in the parrot, the fowls, or the 
ruminating quadrupeds. 
( 1 48.) In reference to the peculiarly loud and dis- 
cordant voices of the Rasorial types among birds, we 
may draw the reader's attention to the singular fact, that 
the very same jmnciple is to be traced m the order 
of quadrupeds which represent the Rasoj'en ; namely the 
Vnyulata, w’hich is typically represented by the rumin- 
ating animals. The loud bellowing ot all the different 
species of oxen, buffaloes, and large antelopes, afford a 
striking contrast to the comparative feebleness of voice 
in most other quadrupeds. The lion is the greatest ex- 
ception, and it has no more influence to invalidate this 
argument, than the musical falcon has to overthrow that 
which proves the Insessorial birds to be the musical 
order. There is nothing gentle or harmonious in the 
bellow'ing of oxen, although, from custom and the asso- 
ciation of ideas, it is not at all disagreeable. The roar 
of a bull we know is terrific, and that of a bison must 
be equally so ; and if not superior, we should think 
fully equal in strength to that of a lion. 
(149.) The NESTS of birds is the last subject which 
strictly belongs to this part of our treatise ; and al- 
though it is replete with much of scientific as well as of 
popular interest, our space will not permit us to treat it 
otherwise than in a general way. With the exception 
of the beavers and a few of the mouse-like Glire.v, birds 
are the only vertebrated animals which construct tem- 
porary habitations. In this peculiarity we have an ad- 
ditional point of analogy between them and the winged 
class {Ptilota') of insects. This instinct seems to be a 
necessary consequence of their oviparous nature ; ior, as 
warmth is essential to the hatching of the egg, it is 
obvious, that, were all to be exposed to the heat of the 
sun, like those of the ostrich, no eggs could be matured 
