OCR Text |
Show 154 DR. F. P. MORENO AND MR. A. S. AYOODAVARD ON [Feb. 21, In fact, so far as the differentiation of the dermal bone is concerned the so-called Neomylodon is precisely intermediate between Mylodon and the existing Armadillo (Dasypus); sections of the scutes of the latter animal, both in the Royal College of Surgeons and in the British Museum, showing that in this genus nearly the whole of the osseous tissue is arranged in Haversian systems, although abundant interlacing connective-tissue fibres are still entangled in it, at least near the border. If the characteristic dermal armature does not suffice for the definite expression of an opinion as to the precise affinities of the specimen, a still less satisfactory result can be expected from a comparison of the hair. For, iu the first place, no hair has hitherto been discovered in association with the skeleton of any extinct Ground-Sloth ; while, secondly, the hairy covering of a mammal is perhaps that part of its organization most readily adapted to the immediate circumstances of its life. So far as their endoskeleton is concerned, the extinct Mylodonts and their allies are precisely intermediate betAveeu the existing Sloths and Anteaters ; they combine " the head and dentition of the former with the structure of the vertebral column, limbs, and tail of the latter " l. It might therefore be supposed that the hair of this extinct group would exhibit some of the peculiarities of that in one or other of its nearest surviving relatives. The epidermal covering of the piece of skiu now described, however, entirely lacks the under-fur which is so thick in the Sloths ; while the structure of each individual hair, with its smooth cuticle and lack of a medulla, is strikingly different from that observed both in the Sloths and Anteaters, and identical with that of the hair in the surviving Armadillos. The large hair in the Sloths and Tamandua exhibits a conspicuously scaly cuticle ; while that of Myrmecophaga is remarkable for its very large medulla. All these animals now live in the tropics, either in forests or swamps, Avbereas the Patagonian animal must have existed under circumstances much like those uuder which the Armadillos still survive. Hence the characters of the hair of the so-called Neomylodon may be of no great importance in determining the affinities of the animal, but may represent a special adaptation to its immediate environment. Finally, there is the question of the antiquity of the problematical skin. On two occasions I have examined the mummified remains of the extinct Mammoth and Rhinoceros from Siberia in the Imperial Academy of Sciences at St. Petersburg; I have also carefully studied the remains of the neck and legs of the Moa from a cavern in N e w Zealand, now in the British Museum. Compared with these shrivelled and dried specimens, the piece of skin from Patagonia has a remarkably fresh and modern aspect; and I should unhesitatingly express the opinion that it belonged to an animal killed shortly before Dr. Moreno recognized its interest, had he not been able to give so circumstantial an account of its discovery and strengthened his point of view by recording the 1 Flower and Lydekker, ' Introduction to the Study of Mammals,' p. 183. |