On Hair in the Bquidse. By F, H. A, Marshall, 
B.A., F.R.S.E. (With Six Plates.) 
(Read June 17, 1901.) 
The taxonomic value of hair has long been recognised. The 
different types of human hair have been made use of as a basis for 
classification of the varieties of Man by Primer Bey* and many 
others, while Waldeyerf in his Atlas has described briefly the hair 
characters of well known members of the Mammalian orders. In 
the present paper it is proposed to deal with hair within the limits 
of a single family, that of the Equidse, and to describe certain 
peculiarities in the hairs of members of that group, which the 
author is of opinion are probably of specific value. But before 
dealing with the hair characters by which the species may be dis- 
tinguished from one another, something must be said about those 
of the group as a whole. 
The characters by which hairs of different animals can be dis- 
tinguished from one another, apart from their length, shape, and 
colour, the latter being of little or no taxonomic value, are the 
nature of the cuticle, the extent of development of the medulla in 
different parts of the hair, the relative thickness of the medulla, 
and the arrangement of the pigment in the cortex. The cuticle 
presents comparatively slight modifications, and consequently the 
characters of this layer are not of much value for taxonomic pur- 
poses. In the hairs of the different members of the Equidse it is, 
so far as I have observed, almost identical, being smooth or only 
slightly imbricate. In transverse sections it appears little more 
than a line bounding the cortex on the exterior. 
The medulla, on the other hand, shows very great variability in 
different animals, and the accounts given of it by various writers 
* Primer Bey, Human Hair as a Race Character,” Jour, of Anthropolog- 
ical Institute , vol, vi. 
t Waldeyer, Atlas des Menschlichen und Tierischen Haare , etc., Lahr ; 
1884. 
VOL. XXIII. 2 B 
