THE MUSEUM 
OF 
NATURAL HISTORY. 
ZOOLOOT. 
VERTEBRATE ANIMALS— (vertebrata.) 
When the immortal Cuvier published his new arrange- 
ment of the Animal Kingdom, he divided all animals 
into four principal sections, which we still find adopted, 
with some modifications, by most naturalists. The 
changes which have been made in the contents of 
these great divisions, in accordance with the progress 
of zoological science since the death of the great 
French comparative anatomist, have principally affected 
the three lower groups established by him, and the 
limits of his first and highest division of animals, that 
of the Vertebrata, have remained without alteration. 
This, indeed, is no more than might have been ex- 
pected. The vertebrate animals are those whose 
existence has always, from various circumstances, been 
pressed most forcibly upon the notice of mankind. 
Vertebrate animals furnish the greater part of our 
daily food, and amongst them are to be found our 
most dangerous enemies, so that the mere instinct of 
self-preservation must have early led even the uncivi- 
lized man almost unconsciously to the study of their 
natural history. Hence, the knowledge of the differ- 
ences and agreements in the structure of these crea- 
tures had made great progress, even in the popular 
mind, at a period when the greatest philosophers 
knew little of the remainder of the animal kingdom ; 
and Linnaeus, in dividing the whole of animated 
nature into six classes, gave no fewer than four to the 
creatures which we now distinguish as Vertebrata. 
The name of Vertebrata or Vertebrate animals, given 
to this great section of the Animal Kingdom, has 
reference to one of its principal characters, namely, the 
possession of a backbone (spine or vertebral column), 
composed of numerous joints {vertebrce) attached firmly 
to each other, but in such a way as, in most cases, to 
insure more or less flexibility. 
The office of this bony column is twofold. In the 
first place, by its enlargement into the hollow case 
called the shull, and by the presence of apertures in 
each of its joints, which, when placed in their proper 
position, form a continuous tube or canal running 
down the back of the animal — it furnishes a protection 
for the brain and spinal marrow (spinal cord), the 
Von. T. I 
great centre of the nervous system, which in these 
creatures attains a high degree of development. In 
the second place, by affording support to numerous 
other bones, varying in form and arrangement accord- 
ing to the duties they have to perform, it consti- 
tutes the centre of the skeleton of these animals — a sort 
of bony framework which at the same time serves 
to protect the more important internal organs, and 
to furnish solid points of attachment for the muscles 
by which the movements of the various parts are 
effected. 
This framework of bones consists, in addition to 
the skull and spinal column already referred to, of the 
ribs, and of the bones of the limbs — the former, as is 
well known, constituting a series of long curved bones 
which inclose the cavity of the chest, and are for the 
most part movably articulated to the vertebrae on each 
side. The opposite extremities of the ribs are also 
usually united to a single bone, which occupies the 
centre of the anterior or inferior surface of the chest, 
called the breastbone (or sternum) ; and in most air- 
breathing Vertebrata the whole framework of the chest 
is capable of moving by the action of the muscles 
attached to the ribs, in such a manner as to increase 
or diminish the size of the cavity inclosed by them, 
thus causing the lungs to be alternately filled with 
and emptied of the air necessary for respiration. The 
vertebrae which bear the ribs are usually distinguished 
by several peculiarities of construction from those of 
the other parts of the spinal column ; they are called 
dorsal vertebrae, or vertebrae of the back; those in 
front of them, forming the neck, are called cervical 
vertebrae, and those behind them, which are usually 
of great size, are called lumbar vertebra, or vertebrae of 
the loins. The latter are followed by the vertebrae 
which support the hinder extremities ; and these again, 
in most of these animals, by a number of vertebrae, 
gradually diminishing in size and completeness, which 
form the tail. These are the caudal vertebrae. 
Of limbs in the Vertebrata there are never more 
than two pairs. The anterior limbs are usually attached 
to the body by being articulated to a pair of flat bones 
