1900 - 1 .] Mr F. H. A. Marshall on Hair in the Equidce. 389 
typical shoulder hair, taken in three places, as with the other speci- 
mens of hairs described in this paper : — 
Breadth of cortex on one side 
of medulla in three places. 
(1) "0144 mm. 
(2) "0162 mm. 
(3) "027 mm. 
Breadth of hair in 
three places. 
*126 mm. 
•153 mm. 
"09 mm. 
In length the shoulder hairs are scarcely more than those of the 
Somali zebra, being usually a little over 5 mm. They are 
appreciably flattened in the middle, agreeing in this respect with 
most equine hairs. A longitudinal striping can be observed in 
some of the hairs. The medulla is not present for a considerable 
distance from the root, and where it arises the hair thickens out 
rapidly as with shoulder hairs from the Somali zebra. On the 
other hand, the medulla extends almost to the hair’s tip. Pig- 
ment of a lighter colour than that of the rest of the hair is present 
throughout the medullaless region in the coloured hairs. Trans- 
verse sections through the hairs of the mane present a circular 
outline. The pigment in the cortical region is evenly distributed 
between the cuticle on the one side and the medulla on the other. 
The line of demarcation between the cortex and medulla is ex- 
tremely irregular instead of being parallel to the cuticle. 
DESCRIPTION OF THE PLATES. 
Plate I. 
Fig. 1. Skin of Burchell’s zebra (Crawshay’s variety). 
Fig. 2. Skin of mountain or common zebra. 
Plate II. 
Fig. 3. Skin of young Burchell’s zebra from British East 
Africa. 
Plate III. 
Fig. 4. Skin of young Somali zebra. 
Plate IY. 
Fig. 5. “ Sir John,” a hybrid between a Burchell’s zebra and a 
skewbald Iceland pony. 
