i a ; 
Anoplotherium is from the upper Eocene of France and 
England only ; there are two or three species. Though 
so early a form, it was much specialised, and its pecu- 
liarities have not been retained in more modern nor exist- 
ing forms. It was about the size of the ass. The teeth 
formed an unbroken series, and, as in man, they were 
uniform in height. The upper molars were much as in 
Palzotherium, and the lower were a modification of the 
same type. Nineteen dorso-lumbar vertebre were pre- 
sent ; the tail was very long, with large chevron bones, 
which are not found in other Ungulata, and from which 
Cuvier somewhat rashly inferred that the animal was 
aquatic. The odontoid process of the axis was simple. 
In the feet there were only two toes before and behind ; 
the metacarpals were quite separate. In one species 
there were four toes in front and three behind. £/o- 
thertum or Entelodon is another form from the lowest 
Miocene. It has been found in the middle of France and 
in the Mauvaises Terres of Dakotah. Its skull was elon- 
gated and somewhat pig-like, but the orbit was completed 
behind by bone. In size it approached the tapir. The 
teeth were somewhat carnivorous, the canines being long 
and bear-like, and the premolars trenchant ; the forty- 
four teeth were present ; the posterior molars were com- 
paratively small, and the last one in the lower jaw had 
scarcely a rudiment of a third lobe. As in Anoplotherium 
there were only two toes on each foot, and the meta- 
carpals and metatarsals were free. 
Of the Suid@ many fossil species are known ; the first 
appear in the upper Miocene of Eppelsheim and Pikermé, 
those in the latter locality much resembling the existing 
forms, the teeth only being less differentiated. There are 
no fossil true pigs in America. In the earlier and middle 
Miocene of Germany and France close allies are found 
in abundance, with the teeth simpler, only four tubercles 
being present, and the last molar not being excessively 
developed. One of these, Amphicherus, had very long 
canines pointing downwards in the upper jaw. Hyothe- 
rium conprises Pal@ocherus and Cherotherium, the 
latter a small animal described by Leidy. There is a 
perfect transition between Palzeochcerus and the fossil 
true pigs. Going further back it is doubtful how the line 
of descent continues. Acertherulum of Gervais may have 
had some relation to it. The American peccaries are 
peculiar in having only three premolars ; in the fore-foot 
the outer toe is much reduced, and in the hind foot it is 
lost ; a canon bone is formed by the metatarsals. Fossil 
peccaries have been found by Lund in Pleistocene caves 
of the United States, and in the American Miocene, 
scattered teeth of pig-like animals are not uncommonly 
met with. 
Of recent hippopotamuses there are two species which 
have been further separated into different genera by Leidy, 
Cheropsis being the smaller and more pig-like ; in it also 
the teeth are not so complicated, and it has two fewer 
lower incisors. In both genera the molars are very 
characteristic, being raised in four cusps, each of which 
in the little worn tooth is trefoiled on the surface ; as the 
tooth gets more used these run together to form ultimately 
a single insula, undulated at the borders. In the Pleisto- 
cene caves and gravels of England, France, Germany, 
and elsewhere, remains of Hippopotamus amphibius are 
numerous, some are larger than existing individuals, but 
they do not otherwise differ. In Sicily a smaller species 
is found in enormous numbers. There are no hippopota- 
muses in the Miocene nor in the lower Pliocene. In 
Madagascar a smaller species used to abound. Dr. 
Falconer, in the Sevalik Hills, found remains of true 
hippopotamus with four incisors, but most from that 
region belonged to a distinct form in which all the six 
were present, and which has been named Hexaprotodon. 
There is no complete bridge between these animals and 
the pigs, and none have occurred in America. 
Dr. W, Kowalevsky has drawn attention to an in- 
“NATURE 
420 
teresting point in the construction of the limbs of the 
different members of this class. He has shown that 
there are two methods by which the extremities may be 
supported on the carpus and tarsus respectively. In one, 
the zzadapiive, the digits as they reduce in number, still 
are only supported by the carpals which originally 
articulated with them in the pendactylate foot. In the 
adaptive method, as the digits reduce, they enlarge their 
bases of attachment on the carpus, and so geta firmer 
support. This latter condition is found in all existing 
Artiodactylates except Hippopotamus. 
Of the Se/enodonts one of the earliest known is Chero- 
potamus from the upper Eocene of Montmartre ; it was 
about the size of a pig, with the molars characteristic, 
presenting five tubercles, three in the anterior row, and 
two behind. Axthracotherium had similar molars, its 
limbs are unknown. Hyopfotamus though but little known, 
was once very abundant ; the species varied in size from 
that of a large rat to that of Axthracotherium ; it is only 
found in the Eocene and early Miocene of Europe and 
North America. The molars were formed on the same 
principle as those in Chceropotamus, but they were more 
drawn out ; the lower formed double crescents with an in- 
ternal tubercle well developed; the typical forty-four 
teeth were present. Most had four toes, and feet very 
pig-like. Kowalevsky found some at Hordle with only 
two, and he has named these Dip/opus. Between Hyopo- 
tamus and Anthracotherium there are many intermediate 
forms, Xzphodon with two toes, Dichobune and Cainothe- 
rium, this last had forty-fourteeth, forming a continuous row, 
and three toes on the feet. Dzchodon was a genus, 
named by Owen from some teeth, of which it possessed 
the full number, andthe molars formed double crescents. 
From this we pass by easy transitions to the Zragudide, 
which have nothing to do with the Musk-deer, as is so 
frequently stated. They are at present confined to South 
Africa, South India, and the adjoining large islands. 
Hyomoschus, the African genus, has survived almost un- 
changed from the early Miocene period. TZragu/as is 
not known fossil. 
An American group here comes in to filla gap. Oveo- 
don, an animal about the size of a sheep, found in the 
early Miocene, is said by Leidy to be quite intermediate 
between the deer and the peccaries. It had forty-four 
teeth, its palate more closely resembled that of the deer, 
and the upper molars formed, as in them, double cres- 
cents. The canon bone was not consolidated, and there 
were apparently four toes. They closely resemble Di- 
chodon. Leidy divides them into three genera, Agvio- 
cherus, Merychyus, and Oreodon. The first of these 
approaches Choeropotamus, and the crowns of the teeth 
were very short. Ge/ocus, described by Kowalevsky, is 
the earliest known form in which the metacarpals coa- 
lesced to form a canon bone; it occurs in the Eocene and 
the earlier Miocene. Those from the former have the 
metacarpals always free, but in the Miocene they anchy- 
losed in the adult animal, and in higher strata they are 
fully coalesced. Dremotherium was a form which closely 
approached the deer. Cervus proper is first represented 
in the upper Miocene. In the earliest forms the antlers 
were very small and simple, closely resembling those of the 
Muntjac, and having long pedicles ; the canines were also 
developed. All the Cervidze adhere to the old type in 
having short crowns and well-marked necks to their 
molars. The Giraffes (Camelopardide) are first known 
from Pikermé and the Sevalik Hills; the molar teeth 
more closely approached those of the deer than any other 
animals. He/adotherium: is not far removed from them ; 
it was of large size and had no horns. Stvathertum was 
the largest of the extinct Artiodactylates. Its bones were 
bovine in character; the metacarpals and metatarsals 
coalesced to form a canon-bone, and there were only two 
toes on each foot ; four horns were present, in pairs, appa- 
rently cavicorn and yet branched, 
