STRUCTURE OF BIRDS. 
25 
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 hairy skin, and in most 
cases shed and renewed annually. 
On the wall is arranged a series of antlers of the Stag 
or Eed Deer [Cervus elaylius), grown and shed (except the 
last) in thirteen successive years, showing the changes which 
took place in their size and form, and the development of the 
branches, or tines, in each year. In old age the number of 
these tines tends to diminish. 
On the north side of the table-case are dissections of the 
principal internal organs of Mammals. 
Bay ISTo. III. is devoted to the class of Birds. An Albatross Bay iii. 
(Biomedea extdans) mounted with the wings expanded shows ^^^^^^.^ 
the most important characters by which a bird is externally of Birds, 
distinguished from other animals. The body is clothed 
with feathers, which (in the majority of birds), by their great 
size and special arrangement upon the fore-limbs, enable 
these to act as orsrans of flight. The mouth is in the form of 
O O 
a horny beak. A nestling Albatross shows that at tliis stage of 
its existence the bird is not clothed with true feathers, but with 
soft down, which serves to keep the body warm, although it 
confers no power of flight. An Emu and Apteryx in the lower 
compartment of the case display the exceptional condition (found 
only in a comparatively few members of the class) of birds with 
wings so small as to be concealed beneath the general feathery 
covering of the body, and quite useless. In the Penguins, 
of which two species are shown in the case, the wings are 
reduced to the condition of fins, and are only serviceable for 
progress through water. 
In the first wall-case the principal features of the skeleton of 
the class are shown. Sections of bones exhibit the large air-cavi- 
ties within ; a complete skeleton of an Eagle, with the bones sepa- 
rated and named, and mounted skeletons of the Ostrich, Peno-uin, 
Pelican, Vulture, Xight -Parrot, Fowl, &c., show the chief modi- 
