61 
OSTEOLOGICAL GALLERY. 
In this Gallery are exhibited the skeletons and skulls of the Mam- 
malia, their order commencing on the left and running round the 
Wall-Cases, as in the Mammalian Gallery. In the centre of the 
room are arranged skeletons which are too large to be placed in 
the Cases, and on the tops of the latter are the horns of the 
^^hollow-horned Ruminants, viz. Oxen, Sheep, and Antelopes. 
The largest skeletons (of Elephants, Giraffe, &c.) are exhibited in 
the Saloon at the end of the Gallery, together with the collection 
of Sirenia or Sea-Cows. 
Visitors who desire to understand the modifications of the bony 
framework of the various types of Mammalia would do well to gain 
some idea of the bones of which a normal Mammalian skeleton 
is made up, and for this purpose the following woodcuts have been 
prepared. Fig. 26 is the skeleton of a Lioness, and fig. 27 the 
skull of a Dog divided down the centre to show its interior. 
The skeleton of a Mammal consists of an axial portion, contain- 
ing the bones belonging to the central axis of the body, viz. the 
skull, vertebral column, ribs, and breast-bone ; and an appendicular 
portion, comprising those which form the limbs, and the girdles of 
bone by which the limbs are attached to the vertebral column. 
The skull is the portion of the axial skeleton which is by far 
the most important to the systematic zoologist, who bases in great 
part his classification of the Mammalia on the variations presented 
by the skull and teeth, which latter, although really no part of the 
internal skeleton, have, from their intimate relation with the skull, 
to be treated as though they belonged to it. 
The skull consists of three parts — (1) the cranium, a compli- 
cated framework of bones united together to form a case for the 
