4 Herr Max Weber on the Origin of Hair 



tion of the formation of rows is still demonstrable. And with 

 reference to hairs we read on page 722 that, contrary to 

 feathers which are arranged in constant rows, '^ they are more 

 uniformly distributed over the entire body ; it is true that 

 they sometimes form rows, but these are not referable to the 

 arrangement exhibited by the scales of Reptiles." 



It is certainly not my intention to call to account the 

 respected author, who is also responsible for this suggestive 

 investigation, for possible trivial discrepancies. These, how- 

 ever, point to the slight extent and the vagueness of our 

 knowledge as to the arrangement of the hair. And yet this 

 very elementary question plays no unimportant part in the 

 whole matter. 



In opposition to Maurer's repeated assertion that the 

 arrangement of hairs is not referable to that of Reptilian 

 scales, I should like to attempt to prove that such may well 

 be the case. 



A close investigation * into the structure and development 

 of the so-called scales of Manis taught me, in connexion with 

 the studies made by Leydig t, that they are horny scutes 

 which rest upon an enormous papilla of the cutis. The latter 

 is a bilaterally symmetrical flattened elevation of the derm, 

 which is bent in towards the tail, and upon which a dorsal 

 and a ventral surface can accordingly be distinguished. 

 Arranged in imbricated fashion, these scales differ from those 

 of Reptiles only in subordinate points, corresponding to the 

 difference which is inherent in the Reptilian and Mammalian 

 integument as such. In consequence of this it is true that a 

 perfect homology between the scales of Manis and those of 

 Reptiles is out of the question ; but I certainly thought it 

 possible to conclude that both arose from common ground, 

 and that even the scales of the Manidfe are structures which 

 are to be derived from the scales of primitive Reptiles. If 

 this conception is correct, v,'e must expect that elsewhere also 

 among Mammals dermal structures still persist which, without 

 making too long a detour, can be traced back to Reptilian 

 scales. This, too, is actually the case. I found a coat of 

 scales upon the tail of Anomalurus^ Myrmecophaga Jubata, 

 ]\f. tamandua, Didelphys, 2Ius, and Castor canadensis. The 

 scales were always — although in different stages of degenera- 

 tion and modification — constructed according to the same 

 type, as is shown at once by my numerous figures. Hairs 



* Max Weber, ' Zoologisclie Ergebnisse einer Reise in Niederland. 

 Ost-Indien,' Leiden, 1892, Bd. ii. p. 5. 



t F. Leydig, Miiller's ' Archiv fiir Anatomie und Physiologie,' 1859, 

 p. 704. 



