MANATEES AND SEA COWS — Order, SIRENIA 
This is a small group of aquatic animals, living along the 
marshy shores of both salt and fresh waters, and feeding 
wholly upon aquatic vegetation. Their geological history 
goes back to the early Tertiary, but previously is quite un- 
known, and their relation to other animals is obscure; the 
prevailing opinion is, that they represent an always aquatic 
line of descent from creodont sources allied to those which 
gave rise to the Ungulata. They are seal-like in general form, 
but far more clumsy, with round heads and almost hairless 
bodies. The hind limbs are absent, only a trace of pelvis 
remaining; the fore limbs are inclosed in a mittenlike web- 
bing, and thus are modified into swimming organs, but there 
is no such multiplication of bones as occurs in a whale’s flip- 
pers; the tail is flattened and either whalelike (forked) or 
paddle-form. The teats are two, and are borne on the chest. 
Of the extinct forms the best known is the great rhytina, which in the 
eighteenth century was found by Russian navigators densely populating 
islands on the Siberian coast of Bering Sea. The naturalist Steller 
was with one of the first expeditions and published an elaborate memoir on 
the animal. It was much like the dugong in form, 20 to 30 feet 
long, weighed 600 to 800 pounds, and its flesh was like beef. It 
lived in herds feeding on seaweed, and could neither defend itself nor escape 
from the seal hunters, who slaughtered it by wholesale for ship provisions. 
All were killed by 1767, and we should know almost nothing of the creature 
had not Stejneger made a special trip to Bering and Copper islands in 1883 
to collect its bones and any information accessible.75! 
A more truly fossil sirenian is Halitherium, which seems to have been 
almost universally distributed during the Miocene period. 
400 
Rhytina. 
