HYR.NODON, Laiz.—With the delicate and beautiful Herbivora of the upper eocene and lower miocene periods, there coexisted carnivorous quadrupeds, which, to judge by the character of their flesh-cutting teeth (carnassials), were more fell and deadly in their destructive task than modern wolves or tigers. Of these old extinct Carnivora a species of the remarkable genus Hymnal-on, of about the size of a leopard, has left its remains in the upper eocene of Hordwell, Hampshire. Fig. 104 shows the dentition of the under jaw of another species of the same genus from miocene beds at Debruge and Alais, France. The carnassial teeth jm,2, 2, 3), instead of being one in number in each ramus of the jaw, as in modern Felines, were three in number, equally adapted by their trenchant shape, to work like scissor-blades on the teeth of the upper jaw, in the act of ting flesh. After the small sors came a pair of large piercing and prehensile canines (c), fol lowed by four compressed pointed and trenchant premolars (p, 1, 2, 3, 4) in each side of the jaw ; the whole of this carni vorous dentition conforming to the diphyodont type :— Genus AMPHICTON.-With the foregoing predecessor of the digitigrade Carnivora was associated a forerunner of the plantigrade mily, viz., a large extinct species having the lars tuberculated, after the pattern of those of the bears ; but taining, like oenodon, the fect type of diphyodont dentition. Fig. 105 shows the teeth of one side of the upper jaw of the Amphicyon giganteus. The first and second molars (nz, and z) have each two tubercles on the outer side and one on the inner side ; the last tubercular molar (2/2, 3 ) is of very small size. Fossil remains of Amphi cyon have been found principally in the miocene deposits at Sansans, south of France. Those of a smaller species from the miocene at Eppelsheim, have been referred to the wolverine genus, as Gulo diaphorus, Kaup.
The proofs of the abundant mammalian inhabitants of the eocene continent were first obtained by Cuvier from the fos silized remains in the deposits that fill the enormous Parisian excavation of the chalk. But the forms which that great anato mist restored were all new and strange, specifically, and for the most part generically, distinct from all known existing quad rupeds. By these restorations the naturalist was first made
acquainted with the aquatic cloven-hoofed Anoplothere, and with its light and graceful congeners, the Dichobunes and Xiphodon, with the great Palwotheres, which may be likened to hornless rhinoceroses, with the more tapiroid Lophiodon, with the large peccari-like Chceropotamus, and with about a score of other genera and species of placental Mammalia.
Almost the sole exception to the generic distinction of these eocene forms from modern ones was yielded by the opossum of Montmartre (Didelphis Gypsorum, fig. 106) ; and what made this discovery the more remarkable was the fact that all the known existing species of that marsupial genus are now confined to America, and the greater part to the southern division of that continent. An opossum appears to have been associated with the Hyracotherium in the eocene sand of Suffolk ; where likewise, a porcine beast with tusks like ordinary canines, and some remains of a monkey (Eopithecus), have been found. With respect to the Didelphis Gypsorum, its generic relations were deduced from characters of the lower jaw and teeth ; but these were associated with other parts of the skeleton in the same block of stone. When Cuvier expressed his convictions from the teeth and other parts first exposed and examined, his scientific associates were incredulous. He invited them, there fore, to witness a crucial test. The outline of the back part of the pelvis was exposed, the fore part buried in the matrix. By his delicate use of the graving-tool, Cuvier brought to light the fore part of the pelvis with the two marsupial bones (fig. 106, a, a) in their natural position. He thus demon strated that there had been buried in the soft fresh water deposits, hardened in after ages into the building stone of Paris, an animal whose genus at the present day is peculiar to America. It is not uninteresting to remark that the Peccari, the nearest existing ally to the old Chceropotamus, is, like the opossum, now peculiar to America ; and that two species of tapir, the nearest living allies to the Lophiodon and Palwothere, exist in South America.