GKOUND FLOOR. 
33 
species of whales, owing to the quantity of oil with which they 
are saturated, the exhibition of the characters of these animals is 
chiefly limited to their skeletons, assisted by drawings of their 
external forms. The general appearance of many of the smaller 
kinds is, however, shown by stuffed specimens and coloured 
casts. A general account of the structure and classification of 
the Cetacea, with special reference to those exhibited in this 
gallery, will be found at the end of the Guide to the Galleries 
of Mammalia.* 
On the left side of the door, on entering, near the window, is a Fresh-wate 
case containing a stuffed specimen, skeleton, and several skulls ^o^P^i^^. 
of the very curious fresh- water Dolpliin of the rivers of India 
(Platanista gangetica), and in the next case the peculiar Dolphin 
of the river Amazon {Inia geoffrensis). Among the specimens 
on the same side of the room, one of the most interesting, on 
account of its remarkable dentition, is the iTarwhal or Sea- Narwlial. 
Unicorn. It has only two teeth, which 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 abortive (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, projecting horizontally from the head in the form of 
a long, straight, tapering and pointed tusk, spirally grooved 
on the surface. In some very rare cases both teeth are fully 
developed, as in the fine skull exhibited near the skeletons. 
Most of the largest Cetacea belong to the group called 
" Whalebone Whales," in which a series of horny plates called whalelione 
''baleen," or more familiarly "whalebone," grow from the Shales, 
palate in place of teeth, and serve to strain the water taken into 
the mouth from the small maruie animals on which the whales 
subsist. A fine representative of this group is the very perfect 
skeleton of the Common Eorqual or Fin-whale (BcdasnojJtera 
mnmilus) near the further end of the middle of the room. It is 
sixty -eight feet long, and was captured in 1882 in the Moray 
rirth, Scotland. The flukes of the tail and dorsal fin are pre- 
* ' Guide to the Galleries of Mammalia ' (Mammalian, Osteological and 
Cetacean) in the Department of Zoology. Price fourpence. 
