156 LÖNNBERG, SOME REMAINS OF NEOMYLODON LISTAI. 



already been pointed out by Ameghino when he (1. c.) named 

 this animal »Neomylodon», the shape and distribution of these 

 ossicles are rather similar to those in the extinct Mylodon. 

 Through the great kindness of Mr. R. Lydekker, to whom 

 1 here wish to express my very best thanks, I have had the 

 great opportuuity to obtain from British Museum of Natural 

 History 3 scutes or ossicles of a fossil Mylodon for com- 

 parison. The likeness l)etween these and the large ones of 

 Neomylodon» is certainly striking, but there are also some 

 differences. The two largest ossicles of Mylodon which I re- 

 ceived from British Museum are larger than any of those in 

 the »Neomylodon» skin. This is, however, evidently subject 

 to Variation as well in Mylodon as in »Neomylodon». The 

 ossicles which Burmeister has figured * in natural size, and 

 which belonged to his Mylodon yracilis (according to Lydek- 

 ker 2 identical with M. robustus Owen) are not much longer 

 than those of »Neomylodom, but as they are broader and 

 more or less quadrangular in shape their size is a good deal 

 larger. As Burmeister alse remarks (1. c. p. 173), the »inner» 

 side is more convex than the >;outer» in the ossicles of Mylo- 

 don, but that is not at all the case, or not conspicously so, 

 in sNeomylodom. With regard to their size the ossicles of 

 Mylodon seem to be comparatively flatter than those of 

 :>Neomylodon». These differences are all of them of less im- 

 portance. But there is another feature in the ossicles of 

 Mylodon, which at once attracts the attention, and that is 

 the small round depressions 3 already described and figured 

 by Burmeister (1. c). They are also present in the ossicles 

 I have received from British Museum and seem to have been 

 characteristic for the dermal ossicles of Mylodon. Of these 

 there is no trace in the ossicles of »Neomylodom, but the 



structure mentioned by Ameghino (1. c. p. 6) as »per- 



forations tres petites» corresponds to the small foramina for 

 the nonrishing blood vessels which, of course, are well deve- 

 loped in »Neomylodon» as well as the »reseau reticulaire* of 

 the same author. These superficial structures should be still 

 more visible if the »Neomylodon> ossicles had been more ina- 

 cerated free from the snrrounding softer tisssues. The like- 



1 Anales del Mus. Publ. de Buenos Aires T. I. PL V. Fig. 8 A, B. 



2 Anales del Museo de La Plata ; Paleontologia Argentina, III, La Plata 

 1894 p. 78. 



:i »Quelques fossettes>. Ameghino 1. c. p. 6. 



