II HAIR AND UNDER-FUR 9 
cular arrangement of the individual hairs among mammals : 
they are not by any manner of means scattered without order, 
but show a definite and regular arrangement, which varies with 
the animal. For instance, in an American Monkey (Midas), the 
hairs arise in threes—three hairs of equal size springing from the 
epidermis close together; in the Paca (Coelogenys) there are in 
each group three stout hairs alternating with three slender hairs. 
In some forms a number of hairs spring from a common point : 
in the Jerboa (Dipus) twelve or thirteen arise from a single hole ;+ i 
in Ursus arctos there is the same general plan, but there is one 
stout hair and four or five slender ones. There are numerous 
other complications and modifications, but the facts, although 
interesting, do not appear to throw any light upon the mutual 
affinities of the animals. Alhed forms may have a very different 
arrangement, while in forms which have no near relationship the 
plan may be very similar, as is shown by the examples cited from 
Dr. Meijerie’s paper. The groups of hairs, moreover, have them- 
selves a definite placing, which the same anatomist has compared 
with the disposition of the bundles of hairs behind and between 
the seales of the Armadillo, and which has led him to the view 
that the ancestors of mammals were scaly creatures 
supported by Professor Max Weber,’ and not in itself unreason- 
able when we consider the numerous points of affinity between 
the primitive Mammalia and certain extinct forms of reptiles.” 
The hairs are greatly modified in form in different mammals 
and in different parts of their bodies. It is very commonly the 
case that a soft under-fur can be distinguished from the longer and 
coarser hairs, which to some extent hide the latter. Thus the 
“sealskin” of commerce is the under-fur of the Ofaria wrsina of 
the North. The coarser hairs may be further differentiated into 
bristles ; these again into spines, such as those of the Hedgehog 
and of the Porcupine. Again, the flattening and agglutination 
fo) 
of hairs seems to be responsible for the scales of the Manis 
a view also 
1 << Bemerkungen iiber den Ursprung der Haare,” Anat. Anz. 1893, p. 415. 
? See for this matter, p. 90. Dr. Bonavia has recently advanced (Studies in 
Evolution, London, 1895) the somewhat fantastic view that the pigment-patches 
of Carnivorous and other mammals are a reminiscence of an earlier scaly condition. 
There is no direct evidence that the primitive mammals were scaly, nor are the 
Monotremata or Marsupials furnished with any more traces of such a con- 
dition than are other mammals; and they are the most lowly organised of existing 
Mammalia. 
