8 Herr Max Weber on the Origin of Hair 
Yet even were the Manide also burrowers in the sense that 
the Dasypodide are, it would certainly be surprising that 
among the large number of most pronounced burrowers 
among Marsupials, Insectivores, and Rodents not a single one 
should have acquired a coat of scales. Further on we read 
(p. 547) :—“ As their embryology shows, both originate from 
true, typical, hair-bearing animals, which in consequence of 
a newly adopted mode of life have acquired a new body- 
covering.’ Much is here demanded of embryology. Yet we 
find in Rémer’s paper no new facts as to the development of 
the integument in Manis, but merely the statement (p. 545) : 
“The origin of the scales, which are strikingly large in the 
case of the small Manide, may well be explained by thie fusion 
of several small scales... .” This mode of explanation is a 
personal one on the part of Romer. I have exerted myself 
to discover the development of the scales on his behalf, from 
their earliest appearance onwards, but have observed no trace 
whatever of a fusion of the scales. Since the investigation 
is a very easy one, I have no reason to deviate from what I 
saw and to adopt an explanation which is not based upon 
observation. 
But also the manner of the occurrence of the scales in 
Mammals tells against the view that they are to be regarded 
as a new acquisition of a secondary character in connexion 
with the mode of life. A few examples may make this 
clear. 
Myrmecophaga tamandua, whose climbing tail is but thinly 
clothed with hair, has the scales but little more strongly 
developed than the exclusively terrestrial MW. jubata, whose 
tail is thickly clothed with bushy hair, and in spite of that 
bears scales. Myrmecophaga (Cyclothurus) didactyla, with an 
exclusively arboreal mode of life and a typical prehensile tail, 
has no trace of scales. Of Pétlocercus and Tupaja, which are 
the only arboreal Insectivores, Ptilocereus has, as shown by 
de Meijere, well-developed polygonal caudal scales, while 
Tupaja, with a precisely similar mode of life, has nothing of 
the kind. Tarscus spectrum of authors comprises, as I was 
able to prove *, two species precisely similar in their mode of 
life. Of these the one, Zarstus fuscomanus, Fisch., has 
distinct scales on a hairy tail, while the almost bare tail of 
the other, 7. spectrum, Pall., is entirely without them. Scales 
were found by de Meijere upon the thickly haired tails of 
Petrogale penicillata and Macropus ruficollis, while in the case 
* Max Weber, ‘Zoolog. Ergebnisse eer Reise in Niederl. Ost-Indien,’ 
Leiden, 1893, Bd. iii. p. 260. 
