IXTEODUCTOEY COLLECTION. 
27 
devoted to tlie Yertebrated Animals, or tliose possessing a 
''backbone." In Xos. I. and II. are shown the characters of 
the Mamnialian modifications of this type. The wall-cases of 
ISTo. I. are already nearly filled with specimens showing the 
bony framework (internal skeleton) of Mammals. 
In the first case (south side of the recess) will be seen a Bay L 
complete skeleton of a good example of the class — a large ^jammals! 
monkey, with all the bones separated, laid out on a tablet, and 
with their names affixed to them. Below it is a skeleton of the 
same animal articulated, or with the bones in their natural 
relation to each other, and also named. By examining these 
two specimens a fair idea may be obtained of the general frame- 
work of the body of animals of this class. In other parts of the 
case are placed examples of modifications of the skeleton to 
suit different conditions of life. 
1. Man, showing a skeleton adapted for the upright position. 
2. A Bat, or flying mammal, in which the fore-limbs are 
converted into mngs by the great elongation of the fingers, 
which support a web of skin stretched between them. 
3. A Sloth, in which the ends of all the limbs are reduced to 
mere hooks, by which the creature hangs back-downwards from 
the boughs of the trees among which it passes its entire existence. 
4. The Baboon serves as an example of an animal walking on 
all four limbs in the "plantigrade" position, i.e., with the whole of 
the palms of the hands and soles of the feet applied to the ground. 
5. A small species of Antelope shows the characteristic form 
of a running animal, in which the limbs perform no office but 
that of supporting the body on the ground. It stands on the 
tips of the toes of its elongated slender feet. 
6. A Porpoise, adapted solely for swimming in the water. 
The fore limbs are com^erted into flattened paddles, and the 
hind limbs are entirely absent, their function being performed 
by the tail. The rudimentary pelvic bones are preserved. 
The rest of the case is occupied by details of the skull in some 
of its principal modifications. At the top are diagrams of the 
structure of bone and cartilage as shown by the microscope. 
In the wall-case on the opposite (north) side of the bay the 
outline of the osteology of mammals is continued by illustrations 
of the structure of the limbs. At the top of the case is a 
