1847.| OWEN ON EXTINCT ANTHRACOTHERIOID QUADRUPEDS, 139 
series, having respectively the dnoplotherium and Paleotherium as 
their types, which genera, so far as our actual knowledge extends 
into the dark vistas of the past, were their first, or amongst their 
earliest representatives on this earth. The known families or genera 
of the odd-toed and even-toed hoofed quadrupeds, respectively 
headed by these two extinct genera, may be ranged as follows: but 
much additional special knowledge must be obtained before their 
order of juxtaposition can be precisely determined :— 
UNGULATA. 
ARTIODACTYLA. PERISSODACTYLA. 
( Anoplotherium. Palezeotberium. 
Chalicotherium. Paloplotherium. 
| Dichobune. Lephiodon. 
! Cainotherium. Coryphodon. 
< | Xiphodon. Tapirus. 
: Moschus*. Macrauchenia. 
< } Antilope. Nesodon. 
€’) Ovis. Hippotherium. 
S Bos. Equus. 
pa | Cervus. Elasmotherium. 
Camelopardalis. Hyrax. 
Camelus. Rhinoceros. 
Mesos. Acerotherium. 
Merycopotamus. 
( Hippopotamus. PROBOSCIDIA. 
4 | Dichodon. Elevh 
ct | Hyracotherium. Ob ea 
z | Hyopotamus. Mastodon. 
2 | Anthracotherium. 
= < Hippohyus. 
pS | Cheeropotamus. 
-y | Adapis (’). 
© | Dicotyles. 
~ | Phacocheerus. 
| Sus. 
The genus Dinotherium appears to make a transition from the 
Tapiroids to the Proboscidians, with an evident tendency also to the 
SrrEN1A; and the genus Toxodon seems to lead towards the Rodentia 
with indications likewise of Sirenoid affinities. With these aberrant 
forms of Ungulata the present communication has no direct concern : 
it bears only upon the affinities of the typical four-footed groups. 
The presence of a divided metacarpus and metatarsus in one existing 
species of Ruminant, the existence of upper incisors and canines in 
another, and the presence of both characters in the embryos of most, 
if not all Ruminants, seem to me to make the assumption that Ano- 
plotherium was not a Ruminant, and its allocation in a distinct order 
* By the presence of the gall-bladder, amongst other family-characters, the 
Antilopes are more nearly allied to the Moschide than the Deer are. 
