28 
CENTRAL HALL. 
also the number and character of the roots by which they are 
implanted. 
Bay II. Bay 'No. II. contains, in its first wall-case (the only one yet 
Intesniment • i\ ^^^ • n i • • t 
of Mammals, occupied), illustrations oi the outer covering or integument and 
its modifications in the class of Mammals, divided into the 
following sections : 
1. Expansion of skin to aid in locomotion, as the webs 
between the fingers of swimming and flying animals, the para- 
chutes of flying animals. 
2. The development of true bony plates in the skin, found 
among mammals only in the Armadillos and their allies. The 
cast of a section of the tail of a great extinct species 
(Glyptodon) shows well a bony external as well as internal 
skeleton. 
3. The outer covering modified into true scales, much resem- 
bling in structure the nails of the human hand. This occurs 
in only one family of mammals, the Pangolins or Manidce. 
4z. Hair in various forms, including bristles and spines. A 
stuffed specimen of a Porcupine at the bottom of the case 
affords a good illustration of a spiny covering. The two 
kinds of hair composing the external clothing of most mam- 
mals, the long, stiffer outer hair, and the short, soft under 
fur, are shown by various examples. 
5. The special epidermal appendages found in nearly all 
mammals on the ends of the fingers and toes, called according 
to the various forms they assume, nails, claws or hoofs. 
6. The nasal horns of the Ehinoceros, shown by sections to 
consist of a solid mass of hair-like epidermic fibres. 
7. The horns of Oxen, Goats and Antelopes, consisting of a 
hollow conical sheath of horn, covering a permanent projection 
of the frontal bone (the horn-core). 
8. The antlers of Deer, solid, bony, generally branched, projec- 
tions, covered during growth with soft vascular hairy skin, and 
slied and renewed annually. 
On the wall at the back of the bay is placed a series of 
antlers of the Common Stag or Eed Deer (Cervus elapJms), grown 
and slied in six successive years, showing the changes which 
took place in their size and form, and tlie development of the 
branches or tynes in each year. 
