ANOPLOTHE'RIUM (from a privative, grXer, and BO, that is, a boast without offensive arms or tusks), in Fossil Zoology, a genus of extinct Pachydermatous Quadrupeds, discovered and characterised by Baron Cuvier. The bones of these singular inhabitants of a former world, occur in great quantities, mixed with those of tho Pahrotherium, another extinct genus of the same order, likewise described by M. Cu vier, in the gypsumatrata or plaAter-quarries in the neighbourhood of Paris, and they are occasionally, though more rarely, met with in the neighbourhooll of Orleans and Genoa. Remains also of this genus have been found in the fresh-water deposits at the Seafield quarries in the Isle of Wight The first character in which the Anoplotheria differ essentially from all other Pachydermata, whether extinct or recent, is found in the number and arrangement of their teeth, which consist of 6 incisors, 2 canines, and 14 molars in each jaw, making in the whole 44 teeth. These, as in the human subject, are arranged in a continued and uninterrupted series, without any vacancies between the molars or incisors and the canines, a circumstance peculiar to this genus of animals among the Pachydermata, and which, besides man, it shares only with the shrews and hedgehogs—Mammalia in all other respects widely different. The canines moreover are perfectly similar in form and appearance to the incisors, and might easily be mistaken for lateral teeth of this description, did not their situation in the jaw, beyond the maxillary suture, prove their real nature. The four posterior molars resemble those of the Rhinoceros and Palmotheria ; that is to say, they are quadrangular in the upper jaw, and marked in the lower with a double or triple crescent of enamel, which penetrates their substance and shows itself on the crowns in the form of salient ridges.
This formation of the organs of mastication, intimately connected as these organs necessarily are with the food and alimentary canal, demonstrate most unequivocally that these animals fed upon vegetable substances, and that, in all probability, they differed but little in this respect from the Tapirs and Rhinoceroses at present existing.
The second important character of the Anoplotheria which must have exercised a very decided influence upon their habits, arises from the conformation of the extremities. These, as in Ruminating Animals, were terminated by two toes, enveloped in small hoofs, sometimes without accessory or false hoofs behind, as in the Camels and Llamas, sometimes with one or even two small lateral toes of this description, as in the Peccaries ; but the bones of the metacarpus and metatarsus respectively corresponding to these two toes were not united into a single canon, as they invariably are among the Ruminantia, and this is in reality the principal difference between the extremities of the latter animals and those of the Anoplotheria. The structure of the
carpus and tarsus is precisely the same iu both genera ; the scaphoid and cuboid bones, which are soldered together into a single piece in all the other Ruminantia, being separate in the Camels and Llamas, as they invariably are in the Anoplotheria and ether Pachydermata.
These analogies prove that the Anoplotherium, which its teeth have already shown to have been essentially a Pachydermatous quadruped, approached in many of its characters to the Ruminantia of the existing creation, partaking on the one hand of the characters of the Camels and Llamas, and on the other of those of the Rhinoceroses and Peccaries. In the less prominent details of organisation however, the different species of A noplotheria present peculiarities which have induced Baron Cuvier to distribute them in three sub-genera. In all, the prolongation of the nasal bones clearly shows that the Anoplotheria were not furnished with trunks like the Elephants, Tapirs, and Pakeotheria ; and their head altogether, judging from the form of the skull, appears to be intermediate between that of the Horse and that of the Camel. The first subdivision comprehends those species which Cuvier calls Anoplotheria proper. They are distinguished by having all the lower molars marked by double or triple crescents in a longitudinal direction, without salient tubercles ; and by a third or supernumerary hoof on the fore-feet. This division comprehends two species, differing from one another principally in point of size, the one (A. commune) being about the size of the ass, and the other (A. secundarium) about that of the hog. Both these species have been found in the Isle of Wight. These animals were low on the limbs, probably like the Tapirs, but their long and powerful tail, equalling the body itself in length, made them still more essentially aquatic animals. The great size of their members, the depressed and heavy proportions of their bodies, and their long tails compressed horizontally at the base, must have given them much of the external form of the otter; but they resorted to the lakes and marshes of the antediluvian world, not for the purpose of preying upon other animals, but in search of aquatic plants, whilst the depressed form of their tails shows that they must have swum and plunged with as much ease and facility as either the Tapir or Hippopotamus. Like these animals their ears were probably short and erect, and their bodies sparingly covered with hair, as in all the existing Pachydermata.