In the first case (south side of the recess) may be seen a complete skeleton of a good example of the class—a Baboon Monkey, with the bones laid out on a tablet, and their names affixed. Below 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 an idea may be obtained of the general framework of the bodies of animals of this class. In other parts of the case are exhibited various modifications of the skeleton to suit different conditions of life.
1. Man, showing a skeleton adapted for the upright posture.
2. A Bat, or flying Mammal, in which, by the great elongation of the fingers, the fore-limbs are converted into wings ([fig. 8]), supporting a web of skin stretched between them.
3. A Sloth, in which the tips of both limbs are reduced to mere hooks, by the aid of 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 the 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. This animal stands on the tips of the toes of its elongated, slender feet in the “digitigrade” fashion.
6. A Porpoise, adapted solely for swimming in the water. The fore-limbs are converted 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.
Fig. 8.—The Skeleton of a Flying-Fox, or Fox-Bat (Pteropus medius).