WHALE EOOM. 
59 
large animals to full advantage. It is also intersected by 
columns, which interfere with the complete view of the larger 
specimens. 
As it is almost impracticable to preserve the skins of the 
larger species of Whales, owing to the oil with which they 
are saturated, the exhibition of the characters of these animals is 
carried out by means of their skeletons and artificial models of 
one side of the external form. Stuffed specimens of many of 
the smaller kinds, are, however, shown. A general account of 
the structure and classification of the Cetacea, with special 
reference to those exhibited in this gallery, will be found in the 
Guide to the Mammal Galleries.* 
On the left side of the entrance is a case containing a stuffed Fresh-water 
specimen, a skeleton, and several skulls of the Susu, or Fresh- 
water Dolphin {Platanista gangetica) of the rivers of India, 
and also of the Dolphins of the Eio de la Plata (Pontoporia 
hlainvillei) and of the Eiver Amazon (Inia geoffroyensis). Among 
the specimens fronting the visitor as he enters the room, one of 
the most interesting, on account of its remarkable dentition, 
is the Narwhal, or Sea-Unicorn. It has only two teeth, which Narwhal, 
lie horizontally in the upper jaw. In the female both remain 
permanently concealed within the bone of the jaw, so that this 
sex is practically toothless ; but in the male, while the right 
tooth remains similarly concealed and rudimentary (as shown 
in the specimen, by removal of part of the bone which covered 
it), the left is immensely developed, attaining a length equal to 
that of half the entire animal, and projecting horizontally from 
the head in the form of a long, straight, tapering and pointed 
tusk, spirally grooved on the surface. In rare cases both teeth 
are fully developed, as in the fine skull exhibited near the 
skeleton, and it is noticeable that in such specimens the direc- 
tion of the spiral is the same in both tusks. 
To the right of the entrance is placed a specimen of the 
bony framework of one of the most colossal of animals, 
the Cachalot, or Sperm-Whale {Physeter macrocephalus), pre- Sperm-Whale, 
pared from an old male cast ashore near Thurso, on the north 
coast of Scotland, in July, 1863, on the estate of Capt. D. 
* " Guide to the Galleries of Mammals in the Department of Zoology." 
Price sixpence. 
