MAMMALIA. 561 
thus there are no teeth, the mandible is much reduced, the jaws are 
long and tapering, the mouth small and the tongue long and mobile. 
The limbs are short and the claws long and powerful. The Pangolins 
are found in East Africa and in the Oriental region (India), and comprise 
one genus. 
Like the Xenxarthra, the Nomarthra are very low types 
of Lutheria, which affect an arboreal or fossorial habit. 
They are confined to Arctogcea, just as the Xenarthra are 
confined to Neogcoea, 
ORDER VI.—Sivenia. 
The Svenia are aquatic herbivorous animals known as 
the Manatees and Dugongs, or sometimes collectively as 
the Sea-cows. They live either in rivers or at the river- 
mouth, and, although well adapted for aquatic habit, they 
do not quite reach the same stage in this direction as the 
Cetacea. As in tke latter, the body is more or less fish- 
like with tapering tail ending in a horizontal “ fluke,” there 
is little or no hair and no pinna to the ear, the fore-limbs are 
in the form of flippers and the hind-limbs are absent. The 
valvular external nares open far back towards the top of the 
head, resulting in the formation of a rostrum, and there are 
retia mirabilia in parts of the body. In all these anatomical 
features the Sivenia are like the Cefacea, but here the resem- 
blance ends. The cervical vertebree are never fused to- 
gether, the teeth are neither absent nor homodont and the 
food consists of aquatic weeds. The flippers usually have no 
more than the normal number of phalanges* (2.3.3.3.3.) and 
the joints of the fore-limb are largely functional, as the flipper 
is used not only for swimming but for assisting food to the 
mouth, and in some cases possibly in holding the young. 
In comparing these characters with the porpoise, it will 
clearly be seen that the Szvenza have not progressed quite 
so far in adaptation as the Ce¢acea. Other special points in 
the anatomy show that there is no true genetic connection 
between the two orders. 
In Stvenia there is the same tendency to disappearance 
of the front teeth as we have noticed in the Ldentata. 
The manatees have no functional incisors nor canines 
* Rarely four, 
M. 37 
