Arctotherium, sp.
With the bones of Felis just noticed, Roth provisionally associates the imperfect distal end of a remarkably large right femur. He is thus induced to suppose that the carnivore represented by the fragments will prove to be a new genus and species of the Felidæ. He suggests for it the name of Iemisch listai, on the assumption that it is the mysterious quadruped which Ameghino states is known to the natives as the Iemisch.
A comparison of the distal end of the femur in question with the femora of Felidæ in the British Museum seems to prove conclusively that it cannot be referred even to the same family. Its width across the condyles is much greater, compared with its antero-posterior diameter, than that observed in any feline. Moreover, the pit for the tendon of the popliteus muscle below the external condyle is unusually deep. In both these respects the bone closely resembles the distal end of the femur of a Bear. I have been therefore led to compare it with the corresponding part of the extinct Bear of the Pampean formation, Arctotherium.
Fortunately, the fine and nearly complete skeleton of Arctotherium bonaerense in the Bravard Collection in the British Museum comprises the right femur and enables direct comparison to be made. The fragment lacks the inner condyle; but enough of the trochlea remains to show its broad and gently-rounded form, with a wide and deep intertrochlear notch, precisely as in Arctotherium. It has the same development of the external condyle as in the latter, while the fossa for the popliteal tendon is equally deep, only slightly differing in shape. In fact, there is very little discrepancy, except in its smaller size; and species of Arctotherium smaller than A. bonaerense are already known both from the Pampa formation of Argentina[58] and the caverns of Brazil.[59]
The fragment just described has evidently been severed from the rest of the bone by a sharp, clean cut made by man; and Dr. Hauthal is quite certain that this was not done by one of his workmen during excavation (op. cit. p. 59). At least one medium-sized species of Arctotherium must therefore have survived until the human period in Southern Patagonia.[60]
Onohippidium saldiasi.
A horse is represented in the collection by an upper molar, a fragment of premaxilla with two incisors, an imperfect atlas and two well-preserved hoofs apparently of a fœtus or perhaps of a newly-born animal. Of these remains only the upper molar is capable of satisfactory determination.
This tooth is the second upper molar of the left side, and has been exhaustively compared with corresponding teeth by Dr. Roth, who gives a good series of figures. It is readily distinguished from the homologous molar in the genus Equus by the peculiar form of its two inner columns—a fact which I have been able to verify by the examination of an extensive series of specimens, both recent and fossil, in the British Museum. Further comparison, indeed, shows that it must be referred to the extinct Pampean genus Onohippidium.[61] Roth assigns it, apparently quite rightly, to the same species as a maxilla from the Pampean formation of the Province of Buenos Aires, for which he proposes the name of Onohippidium saldiasi.
Large Extinct Rodent.