422 UNGULATA 
direction is more irregular. Like the similar but less developed 
air-cells in the skulls of many other mammals, they all communicate 
with the nasal passages, and they are entirely secondary to the 
original growth of the bones, their development having scarcely 
commenced in the new-born animal, and they gradually enlarge as 
the growth of the creature proceeds towards maturity. The nasal 
bones are very short, and the anterior narial aperture is situated 
high in the face. The zygomatic arch is slender and straight, the 
jugal bone being small, and forming only the middle part of the 
arch, the anterior part of which (unlike that of typical Ungulates) is 
Fic. 180.—A vertical section of the skull of the African Elephant (Elephas africanus) taken 
to the left of the middle line, and including the vomer (Vo) and the mesethmoid (ME). 
an, Anterior, and pn, posterior narial aperture. yz natural size. (From Flower’s Osteology of 
the Mammalia.) 
formed only by the maxilla. The maxillo-turbinals are but rudi- 
mentary, the elongated proboscis supplying their place functionally 
in warming and clearing from dust the inspired air. 
The neck is very short. The limbs are long and stout, and 
remarkable for the great length of the upper segment (especially 
the femur) as compared with the distal segment, the manus, and 
pes. Itis owing to this and the vertical position of the femur that 
the knee-joint in the hind leg is placed much lower, and is more 
conspicuous externally than in most quadrupedal mammals; and 
this having been erroneously compared with the hock-joint or ankle 
of typical Ungulates, the popular fallacy that the joints of the 
Elephant’s leg bend in a contrary direction to that of other mam- 
mals has arisen. There is no round ligament in the hip-joint, or 
third trochanter to the femur. The radius and ulna are distinct, 
though fixed in a crossed or prone position. The fibula also is 
