154 DK. F. P. MORENO AND MR. A. S. WOODWARD ON [Feb. 21, 



In fact, so far as the differfintiation of the dermal bone is con- 

 cerned the so-called Neomylodon is precisely intermediate between 

 Mylodon tiwA the existing Armadillo (A(6?/^)us) ; sections of the 

 scutes of the latter animal, both in the Boyal 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, in 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 between 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 " \ 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 skin 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, whereas the Patagonian animal must 

 have existed under circumstances much like those under which the 

 Armadillos still survive. Hence the characters of the hair of the 

 so-called Neomylodon may beof 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 pro- 

 blematical 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 

 cai'efully studied the remains of the neck and legs of the Moa 

 from a cavern in New 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. 



