1900-1.] Mr F. H. A. Marshall on Hair in the Equidce. 385 
considerable space to horse hairs, referring to the characteristics of 
some of the breeds, so it is unnecessary to say anything on this 
subject here. Reference must, however, be made to a character 
upon which lSTathusius, in his earlier papers at any rate, appears to 
lay considerable stress. I refer to the longitudinal striping so 
common in zebra and ass hairs. For some time he regarded this 
character as absent in horse hairs. Subsequently, however, he 
discovered longitudinal striping in hairs of certain ponies of mixed 
breeds imported from Russia. Although I have never observed 
such longitudinal striation in horse hairs, I know of no reason why 
it should not sometimes occur, especially in view of the fact that 
there is considerable evidence, as Professor Ewart* has shown, 
that the horse is descended from a striped zebra-like ancestor, and 
that this longitudinal striation is quite as well marked in the hairs 
of the asses, which are often supposed to have branched off from 
the ancestral equine stock, before the body striping was acquired in 
the Equidse. It must, however, be doubtful how much stress 
should be laid upon such a character as variation in the degree of 
blending and arrangement of pigment, seeing that pigment in the 
other groups of the animal kingdom is known to be especially 
variable and easily influenced by the environment. 
The following are measurements, taken as before, of a typical 
shoulder hair from a bay Irish mare : — 
Breadth of cortex on one side 
of medulla in three places. 
(1) -027 mm. 
(2) -027 mm. 
(3) ’027 mm. 
Breadth of hair in 
three places. 
•054 mm. 
*072 mm. 
*063 mm. 
Asses. 
Ass hairs are very fully dealt with by Nathusius in the two 
papers already quoted. It need only be mentioned here that 
longitudinal striping is very common in the shoulder hairs, and is 
sometimes seen also in those of the mane, and that the hairs 
show a marked degree of flattening, especially those of the Somali 
ass. 
* Ewart, The Penycuik Experiments. London, 1899. 
