1869.) MR. F. H. WELCH ON LEPUS AMERICANUS. 231 
on an equality with the pile of the autumnal coat on the sides, form- 
ing a mottled whity-brown band from ears to tail, contrasting strongly 
with the centre of the back, at present comparatively unchanged; anon 
they outstrip this, reducing the mottling on the sides to a pure white, 
and, gradually implicating the centre of the back in the same process 
(through the varying hue-phases, according as the rapidly advancing 
white growth appears through and finally overwhelms the variegated 
changing autumnal coat), they clothe the animal in a thick white 
outer garment, generally assumed about the first week of December. 
As soon as the new growth renders itself superficially evident, the 
change of colour in the old hair, which on the back up to this time 
has been slow in progress, advances with great rapidity, so that in a 
few days only a few coloured hairs, generally remaining unchanged 
throughout the whole winter, are to be detected. The feet and ears, 
the first to show indications of change, are the last in completing 
the winter hue: generally the head and ears have no hybernal fresh 
growth; but occasionally it is to be met with. During this period, 
and especially when the new hybernal growth of white hair renders 
itself conspicuous on the surface of the autumnal coat, an extremely 
handsome fur is produced; every degree of variation may be met 
with, and each step of the process can be traced with accuracy and 
clearness. Modifications of the progressive changes enumerated 
above often occur in individuals, from an anticipation or retardation 
of change in one part relatively to the whole; these, however, are of 
a temporary nature—mere individual peculiarities, and finally merge 
into the all but universal midwinter clothing, which may be described 
as under. A white, with a leaden tinge, from a few long black hairs 
undergoing no change, pervades the entire skin, with the exception 
of the edges of the ears, eyelids, and legs; a narrow rim of black 
hair, + inch wide, is present at the tip of the ear externally and 
14 inch downwards on each side of the cartilage, which is thrown 
into strong relief by the thick white woolly coat now existent on the 
inside ; a narrow rim, also black, on the free edge of the eyelids ; 
the whiskers white entirely, or interspersed with some not changed, 
the shaft of hair white only at tip, or with alternating white and 
black bands ; the anterior surface of the feet mottled reddish white,— 
the colour of the ears and eyelids being the resultant of no change in 
these situations, that of the feet and whiskers from a non-completion 
of the process. However, although this is the general rule, yet it 
is not difficult to find specimens where the length of the hybernal 
growth on the ears and around the eyes conceals the normal black, 
and the absolute completion of change elsewhere obliterates these 
peculiarities, leaving the animal snowy white, broken only by the 
glistening dark-brown pupil of the eye and yellowish iris. 
Contrasting the winter with the summer and autumnal coat we 
find a colour-change with a great increase in the length and thick- 
ness of the fur ; let us inquire minutely into the process and its local 
modifications. On the back is to be distinguished the pile and 
undergrowth. The former is made up of straight pointed hairs, 
slightly varying in length, the average 1,5, inch, and white through- 
out the entire shaft, mingled with a few isolated black hairs and 
