FIRST FLOOR. 
S7 
Unicorn. It lias only two teeth, which lie horizontally in the 
tipper 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 wiialebone 
" Whalebone Whales," in which a series of horny plates called Whales. 
baleen," or more familiarly whalebone," grow from the 
palate in place of teeth, and serve to strain the water taken into 
the mouth from the small marine animals on wdiich the whales 
subsist. A fine representative of this group is the very perfect 
skeleton of the Common Borqual or Tin-whale (^Balsenoptera 
muscuhos) near the further end of the middle of the room. It is 
sixty-eight feet long, and was captured in 1882 in the Moray 
Firth, Scotland. The flukes of the tail and dorsal fin are pre- 
served with the skeleton and suspended in their natural position, 
and the small pelvic bones and a rudimentary nodule, represent- 
ing the femur or thigh bone, the only trace of the hind leg of 
this gigantic animal, are also preserved. Beyond this skeleton is 
a skull of the Greenland Eight- Whale (Balance mysticetus) which 
yields most of the whalebone " of commerce, and also a small 
wooden model of the animal, of the scale of one inch to the foot. 
First Floor. 
The upper floors of the wings of the Museum consist only 
of single galleries extending along the whole front of the 
building ; the galleries which run backwards on the ground 
floor containing only a single story. 
The ]\Iammaliax Gallery is entered from the western Gallery of 
corridor of the Central Hall. It contains the series of stuffed ^^^malfl. 
specimens of animals of this class, with the exception of the 
Cetacea and the Sirenia. Skeletons of the most important types 
