PACHYDERMATA. 
degree of developement of the snout of the Pig 
and the semi-proboscidean nose of the Tapir. 
The following genera of Pachydermatous 
Quadrupeds have been distinguished by natu- 
ralists, many of which are still in existence, 
but the majority are met with only in a fossil 
State, the names of the latter being printed in 
italics. 
Elephas, (fig. 464. ) Hippopotamus 
Mastodon Toxodon 
Dinotherium Coryphodon 
Tapirus Acerotherium 
Paleotherium Elasmotherium 
Lophiodon Macrauchenia 
Hyrax Hexaprotodon 
Rhinoceros Anthracotherium 
Anoplotherium Cheropotamus 
Dicotyles Hyracotherium 
eT Dichobune. 
us 
Osseous system.—The skeleton of the Pachy- 
dermata is generally remarkable for the massive 
character which is conspicuous in every region, 
indicative, at a glance, of the ponderous strength 
and generally inactive habits of the animals 
belonging to this order; but inasmuch as they 
are destined to obtain their food under very 
various circumstances, which demand a cor- 
responding diversity of structure in different 
of their bony framework, some detail will 
necessary in adverting to this part of their 
economy. 
Cranium.—The cranium of the Elephant, the 
only living genus of Proboscidian Pachyderms, 
is quite unique in its external configuration, 
and from its vertical elevation confers a re- 
markable aspect of sagacity to the animal ; its 
intelligence, however, although really surpri- 
sing when contrasted with the stupidity of 
other genera belonging to this class of quadru- 
peds, has doubtless been much exaggerated in 
consequence of its imposing appearance. This 
peculiar contour of the skull depends upon 
several circumstances having nothing whatever 
to do with cerebral developement, but being 
entirely dependent upon mechanical arrange- 
ments required to support the enormous tusks 
that project from the upper jaw, and to give 
origin to the muscles of the proboscis, a nasal 
apparatus here only met with in a state of 
complete developement. The extreme short- 
ness of the bones of the nose, the nearly vertical 
position of the upper maxilla and ossa incisiva, 
and the swollen vault of the forehead produced 
by an excessive enlargement of the frontal 
sinuses, (fig. 466, ) which gives extent of sur- 
face to the exterior of the skull, all concur to 
mask the real condition of the cranial cavity, 
which, as is easily seen in the next figure, 
(fig. 465,) occupies but a very small portion of 
the posterior and central portion of this gigantic 
cranium. 
The general character of the individual bones 
of the cranium and their modifications in the 
principal Pachydermatous races will be under- 
stood from the appended figures better than 
from any lengthened description. 
The occipital bone is very extensive, forming 
by itself the entire posterior wall of the cranial 
859 
Skull of young Indian Elephant. 
a, intermaxillary bone; 6, nasal bone; c, superior 
maxillary; d, jugal; f, frontal; g, parietal; 
h, temporal ; 2, inferior maxilla. 
cavity, and even in the Elephant advancing 
considerably upon its upper surface, where at an 
early period it becomes so firmly consolidated 
with the parietals, and these again with the fron- 
tals and temporals, that the whole roof ofthe skull 
appears to be formed of one bone. In the hog 
tribe, the Hippopotamus and the Tapir, it termi- 
nates superiorly in an abrupt and broadly ex- 
panded crest, into which the muscles of the neck 
are inserted ; and not unfrequently the deep fossz 
and prominent ridges visible upon its posterior 
aspect testify to the massive strength required 
in this part of the muscular system, either to 
Vertical section of Elephant’s skull, shewing the relative 
ortions between the cranial cavity and the sinuses 
of the skull. 
