314 THROUGH THE HEART OF PATAGONIA 



to me, but I had hesitated to mention it on account of the considerable 

 discrepancy observable between the arrangement of the bony armour in 

 Ncouiylodoi and that in the known Glyptodonts and the unique Brazilian 

 Armadillo {Scleroplcjira), which happen to exhibit an incompletely 

 developed (incipient or vestigial) shield. In each of the latter cases, the 

 armour is not subdivided into a compact mass of irregular ossicles, but 

 consists of well-separated elements which could only become continuous 

 by the addition of a considerable extent of bone round their margins, or 

 by the special development of smaller intervening ossicles. 



Since the paper was read, I have had the privilege of studying Dr. 

 Einar Lonnberg's valuable description of the pieces of the problematical 

 skin mentioned by Dr. Moreno as having been taken to Upsala by Dr. 

 Otto Nordenskj()ld.* It appears that with the skin was found the 

 epidermal sheath of a large unknown claw, which may have belonged to 

 the same animal. This specimen proves to be different from that of any 

 existing Sloth, Anteater, or Armadillo, and is considered by Dr. Lonnberg 

 to belong probably to the hind foot of a Mylodont, which did not walk 

 on the exterior, lateral surfaces of the toes to the same extent as Mylodon. 

 In a section of the skin provisionally ascribed to the leg, he observes that 

 the small ossicles are very irregular, and shows two instances in which two 

 are placed one above the other. In microscopical sections of the ossicles, 

 however, he does not find the distinct Haversian systems of bone so con- 

 spicuous in my slides ; and hence he fails to remark the differences 

 between the structure of the armour in Neomylodon and Mylodon, which 

 seem to me to be particularly noteworthy. His so-called " pigment 

 cellules " in Mylodon are the dendritic infiltrations of oxide of manganese 

 and stains of oxide of iron, to which I have made special reference. His 

 observations as to the absence of a medulla in the hair confirm my own ; 

 but I have not seen any evidence of the suspected loss or disintegration 

 of the hair-cuticle. Finally, Dr. Lonnberg has boiled a piece of the skin, 

 thereby extracting glue, " which proves that the collagen and gelatinous 

 substances are perfectly preserved." The latter observation confirms the 

 evidence of the serum recorded above, and indicates that if the specimen 

 is " of any considerable age, it must have been very well protected against 

 moisture and bacteria." — A. S. W.] 



* E. Lonnberg, "On some Remains of 'Neomylodon listai,' Ameghino. brought home 

 by the Swedish Expedition to Tierra del Fuego, 1895-1897," Wissensch. Ergebn. 

 schwedisch. Exped. Magcllansliind. iinter Leitung v. Otto Nordenskjold, vol. ii. 

 pp. 149-170, pis. xii.-xiv. (iSgg). 



