254 THE HISTORY OF CREATION, 
Mammals, are most closely allied to Hoofed animals, and 
more especially agree with them in the absence of the 
decidua and in the tufted placenta. Even at the present day 
the river-horse (Hippopotamus) constitutes a kind of transi- 
tion form to the Sea Cows (Sirenia), and from this it seems 
most probable that the extinct primary forms of the Cetacea 
are most closely allied to the Sea Cows of the present day, 
and that they developed out of Pair-hoofed animals, which 
were related to the hippopotamus. Out of the order of 
Herbivorous whales (Phycoceta)—to which the sea cows be- 
long, and which accordingly, very probably, contain the 
primary forms of the legion—the other order of Carnivorous 
whales (Sarcoceta) appears to have developed at a later 
period. But Huxley thinks that these latter were of quite a 
different origin, and that they arose out of the Carnaria 
through the Seals. Among the Sarcoceta, the extinct gigantic 
Zeuglodonta (Zeugloceta)—whose fossil skeletons some time 
ago excited great interest, it being thought that they were 
“sea serpents’—are probably only a peculiarly developed 
lateral branch of genuine whales (Autoceta), which com- 
prise, besides the colossal whalebone whales, the cachalot or 
spermaceti whales, dolphins, narwhals, porpoises, ete. 
The third legion of the Indeciduata, or Sparsi-placentalia, 
comprises the strange group of the animals poor in teeth 
(Edentata); it is composed of the two orders of burrowers 
and sloths. The order of Burrowers (Effodientia) consists 
of the two sub-orders of ant eaters (Vermilinguia), to 
which the scaled animals also belong, and the girdle 
animals (Cingulata), which were formerly represented by 
the gigantic Glyptodons. The order of Sloths (Tardigrada) 
consists of the two sub-orders of the small, still living 
