300 HISTORICAL PALASONTOLOGY. 
which the teeth differed from those of all existing forms in 
being of two kinds,—the front ones being conical incisors, 
whilst the back teeth or molars have serrated triangular 
crowns, and are inserted in the jaw by two roots. Each 
molar (fig. 228, A) looks as if it were composed of two 
separate teeth united on one side by their crowns; and it is 
this peculiarity which is expressed by the generic name (Gr. 
zeugle, a yoke ; odous, tooth). The best-known species of 
the genus is the Zeuglodon cetoides of Owen, which attained 
a length of seventy feet, Remains of these gigantic Whales 
are very common in the “Jackson Beds” of the Southern 
United States. So common are they that, according to Dana, 
‘the large vertebree, some of them a foot and a half long and 
a foot in diameter, were formerly so abundant over the 
country, in Alabama, that they were used for making walls, or 
were burned to rid the fields of them.” 
The great and important order of the Hoofed Quadrupeds 
( Ungulata) is represented in the Eocene by examples of both 
ot its two principal sections—namely, those with an uneven 
number of toes (one or three) on the foot (Perissodactyle Ungu- 
éates), and those with an even number of toes (two or four) to 
each foot (Artiodactyle Ungulates). Amongst the Odd-toed 
Ungulates, the living family of the Tapirs (Ti apiridé) 1s repre- 
sented by the genus Coryphodon of Owen. Nearly related to 
the preceding are the species of Padeotherium, which have 
a historical interest as being amongst the first of the Tertiary 
Mammals investigated by the illustrious Cuvier. Several 
species of Paleothere are known, varying greatly in size, the 
smallest being little bigger than a ‘hare, whilst the largest must 
have equalled a good-sized horse in its dimensions. The 
species of Paleotherium appear to have agreed with the 
existing Tapirs in possessing a lengthened and flexible nose, 
which formed a short proboscis or trunk (fig. 229), suitable as 
an instrument for stripping off the foliage of trees—the char- 
acters of the molar teeth showing them ‘to have been strictly 
herbivorous in their habits. They differ, however, from the 
Tapirs, amongst other characters, in the fact that both the 
fore and the hind feet possessed three toes each ; whereas in 
the latter there are four toes on each fore-foot, and the hind- 
feet alone are three-toed. The remains of Paleotheria have 
been found in such abundance in certain localities as to show 
that these animals roamed in great herds over the fertile plains 
of France and the south of England during the later portion 
of the Eocene period. The accompanying illustration (fig. 
229) represents the notion which the great Cuvier was induced 
