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 +, 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 Manide are structures which 
are to be derived from the scales of primitive Reptiles. If 
this conception is correct, we 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, 
M. tamandua, Didelphys, Mus, 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, ‘Zoologische Ergebnisse einer Reise in Niederlind. 
Ost-Indien,’ Leiden, 1892, Bd. ii. p. 5. 
te Leydig, Miller’s ‘ Archiv fiir Anatomie und Physiologie, 1859, 
p- 704. 
