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Proceedings of the Eoycd Society 
seen in Plate XXIV. fig. 1, which represents the appearance of a 
coarse hair taken from the fleece of a Cheviot sheep. 
Along with this external structure there is, in true hair, usually 
associated an internal arrangement of the cells composing the cortical 
substance in which there is a tolerably distinct medullary axis with 
large and well-formed nucleated cells. Such a structure is repre- 
sented in Plate XXI Y. fig. 2, which is a longitudinal section of the 
same hair given in fig. 1. 
Sometimes, however, the medullary axis has a different structure 
even where the external likeness is very similar. This structure is 
is seen in Plate XXIV. fig. 3, and was drawn from a section of a 
coarse hair taken from the fleece of a Pacpathian sheep. In 
this fibre the cells are much smaller and more numerous, and in 
some parts having a distinct granular pigmented appearance and 
non-nucleated. 
In most cases the cells composing the cortical substance of hair 
are distinctly nucleated, but they vary very much in this respect. 
The shaft of the hair is usually firm and straight, and the epidermal 
scales are horny and dense. 
In wool the epidermal scales are attached to the cortical substance 
much less firmly than in the case of hair, and their free margin is 
more prominent, so that the edges of the scales are much more dis- 
tinctly seen and the denticulation at the edge of the fibre is more 
marked. The contour of the free margin of the scales is also 
generally less rounded than in those of the hair, and in the finest 
classes of wool is frequently serrated in a more or less irregular 
manner. The scales are also less horny and dense than those of 
hair, and possess a transparent or translucent appearance like wax 
or gelatine. A typical illustration of a wool fibre is given in Plate 
XXIY. fig. 4, which represents a fibre taken from a fine merino sheep. 
In this fibre the looseness of the attachment of the scales and the 
well-marked serration of their free margins are distinctly seen. 
The looseness of the attachment of the epidermal scales are 
in some classes of wool even more marked than in the merino 
fibre. Plate XXIY. fig. 5 represents a fibre taken from the Chinese 
sheep ( Morvant de la Chine). In this fibre the scales are large and 
well defined, with a horny structure more approaching to that of 
true hair, but with such a small attachment to the stem of the fibre 
