162 LÖNNBERG, SOME REMAINS OF NEOMYLODON LIST AI. 



section of such a hair thiis sliows that the hair of »Neomylo- 

 don» is a solid cylinder of a yellowish (on thin sections nearly 

 white) lme with very minute airfilled pores, scattered through 

 the solid mass. Longitudinal sections snow that these pores 

 are very short and, as it seems, not connected with each other. 

 The hair has a certain tendency to split in longitudinal direc- 

 tion. The thickness of the hair in dry state is about 170 ,«. 



The reddish hair from the hairballs described above is 

 quite different in structure as it has a well developed cent- 

 ral pith and its solid bark is rieh in pigment. 



For comparison I have also raade sections through the 

 hairs of several different South American Edentata. But the 

 greatest nuinber of these differ, as is already wellknown, in 

 being provided with a central pith. The solid crust round 

 the pith of the hair of Dasypus sexcinetus shows however a 

 certain resemblance in structure and consistency to the hair 

 of »Neomylodon». The greatest likeness to the »Neomylodom 

 hair is foilnd in the central axis of the hair of Bradypus. 

 The likeness was so great indeed that I immediately began 

 to look for some traces in the »Neomylodon» hair of a matter 

 corresponding to the exterior loose and pithy-looking bark 

 of the Bradypus hair. I saw very often, almost on every 

 hair of »Neomylodon», brownish specks attached to the sur- 

 face. These were sometimes very thin and without any struc- 

 ture, sometimes there was a layer of considerable thickness, 

 but usually not of very great extension. This is to be 

 found as well on transversally cut sections of the hair as on 

 whole hairs laid under the microscope, and always shows the 

 same brownish colour and has the same appearance every- 

 where. On transverse sections through the skin which cut 

 the hair longitudinally there also seems to be an outer looser 

 layer surrounding the solid axis of the hair in the hair sheath. 

 Horizontal sections through the skin which cut the hair trans- 

 versally seem sometimes to show two rings round the solid 

 axis of the hair. The peripherica! of these is the epithelial 

 hairsheath, the inferior should then represent the loose outer 

 bark of the hair, derived from the cuticula. It is not easy 

 to get a good view of these things for several reasons, among 

 others because the material is old and dry, and the sections 

 are not easy to prepare when the inferior axis is so much 

 harder than the surrounding material so that it usually jumps 



