664 
Proceedings of the Royal Society 
from the alpaca goat is very closely allied to true hair, and exhibits 
many of its characteristics. It is most like hair in its external 
structure, while it resembles wool in the arrangement of its cortical 
cells. Mohair, although usually called hair, is far more like wool 
than alpaca, but it never possesses the same curl and suppleness 
in the fibre which is exhibited by true wool. 
When the fibres of alpaca are examined under the microscope 
their close relationship to true hair is easily seen, and this relation- 
ship extends to the internal as well as the external structure. 
Many of the fibres show a distinct medullary axis with large 
nucleated cells, which frequently contain large quantities of pig- 
ment. In some cases, where this is not distinctly manifested, 
there is an enlargement of the cells in the central axis, although 
they do not differ in any other respect from the remainder of the 
cortical part. Plate XXIY. fig. 9 is taken from a coarse fibre of 
Chala alpaca. The epidermal scales are well marked with rounded 
edges, and, like all alpaca fibres, possess a very high lustre. Some 
of the fibres, when perfectly clean and seen by reflected light, have 
the appearance of burnished silver. Plate XXIY. fig. 10 gives the 
same fibre when viewed with transmitted light, in which the large 
medullary cells are distinctly seen, while the cortical part has a fine 
granular appearance, without any cellular structure being visible. 
The fibres from the Angora goat have a close resemblance to 
those of alpaca, but there is always in them a greater looseness of 
the cuticular scales ; and while they retain the high surface lustre, 
there is a greater tendency to the dispersion of light when seen 
with reflected light. The scales are also more transparent, and of a 
less horny nature. The distinguishing feature, however, is that 
the free margins of the scales are not so smooth and rounded at the 
edges, but show signs of the same denticulation which is so promi- 
nent a feature in true wool ; so much so that many of the fibres in 
the better qualities of mohair can only with difficulty be distin- 
guished from the bright-haired English wools, such as Lincoln or 
Leicester, except that the scales are rather smaller and more regular, 
and that there is less tendency to curl. Plate XXIY. fig. 1 1 is taken 
from a fibre of mohair, and may be compared with the alpaca 
fibre given in fig. 9, and the finer fibre of Lincoln wool given in fig. 
8, when the distinction already noticed will be easily seen. 
