Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/600

 p. 190). The Chalicotherian fossils are said to be in this latter state ; but both bone and dentine of the original specimens in the British Museum are more mineralized and discoloured by the matrix than is the tooth from China here described.

The correspondence, in colour, chemical condition, matrix, and cavernous locality, of the tooth of Chalicotherium sinense with those of Bovine and other Ruminants, of Hyaena, Rhinoceros, and Tapir, which are alleged, and with every appearance of truth, to be from the same cave, supports the inference of a correspondence of geological age in regard to the introduction therein of the individuals of those genera and families which have yielded the remains now described. If the Anoplotherioid molar had not been in the series, such series would have been referred, without hesitation, to a geological period not older than Upper Pliocene, and with a possibility of Postpliocene age.

I accept the evidence of the majority of the fossils, with the older alternative, and conclude that this particular anoplotherioid Artiodactyle which has departed from the generalized character of the type- genus by the suppression of a premolar on each side of both jaws, and the commencement of a diastema or break in the dental series, continued to exist in China until the pliocene division of tertiary time, perhaps to a late period of that division.

I may remark that the Chalicotherian modification has not hitherto been found in older tertiary deposits than miocene. It indicates the course or characters of derivative change in the Artiodactyle series, in a manner interestingly analogous to that shown by Anchitherium and Acerotherium in the Perissodactyle series.

In both great primary groups of hoofed Mammals this change is manifested, in the dental system, by arrest of development at the fore part of the series, especially in the upper jaw. When no teeth there arrive at full growth, the offensive and defensive weapons called horns usually make their appearance ; median and odd in the Perissodactyle Rhinoceros, in a pair or pairs in the Artiodactyle ruminants, with well-known exceptions, not, however, affecting a statement of general tendency. Chalicotherium, in the diminished size of the premolars, in the transverse disposition of the incisive alveoli of the mandible (traces of which are visible in the original of the figure 1, pl. 80, of the ' Fauna Antiqua Sivalensis '*), and in the contiguous small canines, makes a close step to the Ruminant dentition, as it does also in the molar formula, p ______, m _____, and in the diastema between these and the fore teeth. Upper canines as well as incisors failed, as in most Ruminants, to attain development. This view of Chalicotherian modifications in the Artiodactyle series may not meet with general acceptance ; but I think it is preferable to the notion of Chalicotherium having been a kind of cross between Anoplotherium and Rhinoceros.†

now in the Museum of the Marischal College, Aberdeen.
 * Originally in the Dadoopoor Collection of Messrs. Baker and Durand, and

† Falconer characterizes the Chalicotherium sivalense as " one of the most