80 
FOSSIL MAMBIAL GALLERY. 
short tails, strongly-built bodies, and in disposition by their 
remarkable courage and ferocity. They are represented in 
Europe, Asia, and North Africa by the genus Siis, of which the 
Wild Boar, S. scrofa ( 1345 ), is the typical species. A specimen 
of the nearly allied Indian Wild Boar, S. cristatus ( 1346 ), is 
shown in the same case. The Pigmy Hog, S. salvanins ( 1351 ), 
of Nepal and Assam, is noticeable for its diminutive size. 
Other Old-World species are the Bornean S. harhatiis ( 1348 ), 
the African Bush-Pigs, P otamochoerus 1350 ), Forest-Hog, 
Hylocliceriis ( 1352 ), Wart-Hogs, PJiacochwrus ( 1353 , 1354 ), and 
the Babirusa, Bahirusa alfurus ( 1355 ), of Celebes, a hairless 
species with upwardly-curved tusks. 
In the New World the Pigs are represented by the Peccaries, 
Bicotyles ( 1342 - 1344 ), which are smaller than a Wild Boar, and 
differ in their skulls and dentition from all Old-World Suidoi. 
Order YII. SIRENIA, or Sea-Cows. 
(Fossil Mammal Gallery, Geological Department.) 
The members of this order differ strikingly in structure from 
all the foregoing, on account of their aquatic habits and want of 
hind-limbs. They have rounded heads, very small eyes, no 
external ears, a pair of fore-flippers, capable of being moved in 
all directions, no hind-limbs, and broad flattened tails, placed 
horizontally ; while the skin is thick and nearly hairless, the 
lips alone being covered with stiff bristles. 
Most of their bones are extremely dense and heavy, especially 
the ribs ; of the hind-limbs two rudimentary pelvic bones, but 
no trace of true limb-bones, remain in the existing species. 
The earlier tail-vertebrse have well-marked chevron-bones 
attached to their lower surfaces ; and in one genus {^Manatud) 
there are only six cervical vertebra?, one of the few exceptions 
to the general Mammalian number of seven. The fore-limbs 
are developed into flat flippers, not showing externally any 
trace of toes. 
The skull is of peculiar shape and structure, the front part of 
both jaws being bent downwards nearly vertically. The molars 
