FKESHWATER DOLPHINS. 
45 
galleries already completed. The room has, unfortunately, 
the disadvantage of being too small to display such 
large animals to full advantage. It is also intersected by 
columns, which interfere with the complete view of the larger 
specimens. Nevertheless, the specimens will be safely preserved 
in it, until the erection of the west front shall afford them 
better accommodation; and visitors can, with very little difficulty, 
study most of the important peculiarities of these gigantic and 
very interesting members of the Animal Kingdom. 
As it is almost impracticable to preserve the skins of the larger 
species of whales, owing to the quantity of 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 Galleries of Mammalia.* 
On the left side of the entrance is a case containing a stuffed Fresh-water 
specimen, skeleton, and several skulls of the curious Fresh- 
water Dolphin of the rivers of India {Platanista gangetica), 
and also of the Dolphins of the Eio de la Plata {PoQitoporia 
Uainvillei), and of the river Amazon (Inia geo^royensis). 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 
1 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 tlie 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 
j teeth are fully developed, as in the fine skull exliibited near the 
' skeleton. 
* ' Guide to tlie Galleries of Mammalia in the Department of Zoology. 
Trice sixpence. 
