S. kertmdrenii, S. splendidus, S. cmnamomeus, S. siamensis, S. splendens, S.germmi.
S. boctmrtii, and S. leucogaster. The extreme limit of their range is from Assam m a
south-easterly direction through Burma and Siam to the Islands of Bulo Condor
and Sichang. The colour of their fur is most diverse, varying from deep maroom
chestnut to red, and from grey-grizzled to intense blank and to pure white, while
others are spotted with brown on a white ground. In all of these squirrels the
relative proportions of the parts are the same, but all the grizzled forms are small,
and their skulls prove that they are young. These immature forms are S. siamensis,
Gray, and S. leucogaster, A, M.-Edwards.. S. ferrugmeus, S. kertmdrenii, S. cisma-
momeus, and S. splendidus are all rich red squirrels, while S. germcmi is a jet black
and S. finlaysoni a pure white form; whereas S. bocowtii is also white, but marked
by great brown spots. These differently coloured squirrels are thus far distinctive
of localities or rather of geographical areas; none but the pure red forms have
been found to the west of Assam and .Burma. All the other phases or varieties are
apparently confined to Siam.
As I have personally studied the types of all these supposed species, I propose ,
to indicate their, leading features and those tendencies which they show towards
specific unity.
The type of S. finlaysoni was obtained in Siam by Dr. Pinlayson, and another
was procured by the same traveller in Sichang Island off the coast of Siam.
These two specimens are exactly alike, being white squirrels with a yellowish tinge.
The feet, however, show a tendency to become dark or even blackish, especially on
the toes, which is a character of the red form of Assam and Burma, while it is
seldom observed in the red squirrels of Siam. A few of the hairs on the head and
tail have black tips, but their presence makes little impression on the pale fur, except
on the tail. The whiskers are black. In other specimens from Siam, however, I
have observed the white fur generally so intermixed with black hairs that a
remarkable grey colour was communicated to the squirrels presenting this peculiarity.
In'these forms, the black occurs chiefly along the upper surface of the
back, on the shoulder, outside of the fore limbs and thighs, and on the proximal third
of the.tail; the under parts being pure white, Erom the. profusion with whibh
these black hairs occur, the production of the black S. germam is only a question
of degree, and, as it does not involve any structural difference between the two, but
is solely brought about by the deposit of black pigment to a greater extent
than in S. finlaysoni, there seems no reason why these white and black squirrels
should be regarded in any other light than varieties.
There is much greater difficulty attending the verbal explanation of the re-
lations that exist between S. bocmrtm and S. ferrugmeus, but some additional light
is thrown on them by considering the forms which have been referred to S. siamensis
and iS. leucogaster, both-of which are young squirrels.
With regard to S. bocourtii, this squirrel can he best described as a piebald
S. finlaysoni. I t is also from Siam, and is distinguished by the following leading
features, which are subject, however, to considerable variation. The rich brown of
the upper fur extends on to the outside of the limbs and to the tail, but the feet in
some are white. The muzzle, and around the eyes, and the whole of the under
parts, and inside of the limbs, are of a pure ermine tint, like that which distm*
guishes the under parts of S. finlaysoni, but in some specimens the head is wholly
white to behind the eye. The ears are generally white, clothed with grey hairs
on their backs, and with rufous hairs at their bases superiorly. The brown portion
of the pelage is finely and sparsely punctulated with rich yellow. The tail is
broadly ringed with black and yellowish, and the tip tends to become rufous;
but in others, its under surface is wholly white, and its last third pure rich maroon-
chestnut, the tip tending to black; while, in one specimen, the last third of the tail,
as in S. Jceraudrenii, is washed with white. This squirrel, therefore, is a mixture
of the characters of S. finlaysoni, and, as we shall presently see, of those of immature
examples of S. cmnamomeus, which is only a local race or variety of S. ferrugmeus..
S. leucogaster is a young squirrel from Siam, which is undoubtedly the young
of S. siamensis, with immature examples of which it agrees except in its white
under parts, but, at the same time, it is apparently younger than the grizzled and
brownish immature specimens of S. siamensis which have come under my observation.
This young squirrel, besides having the under parts pure white, is marked
above and below the eye with the same colour, but the white under surface is no
more specific than would be the white under surface of S. gordoni or the occasional
grey surface of S. lokriah. The fur of the body and tail generally is grizzled
much as in S. lokroides, but there is a commencing blush of rufous on the head,
from the muzzle backwards on to the tail. S. leucogaster is unmistakeably connected
with S. siamensis by specimens with rufous under surfaces, and which do not
differ from it in any other respect except in being slightly more rufous; but the
evidence which these afford of the specific identity of S. leucogaster with them,
although it cannot well be given in a written description, carries conviction through
the eye- The feet in these apparently immature squirrels tend to black, which is a
significant fact, considering the circumstance that, in the adults of the western red
squirrel, the feet always partake more or less of that colour, whereas, in the adults
from Siam, the extremities differ but little from the body colour. The conclusion
arrived at from these facts is, that in the very young state of S, cmnamomeus the
belly is, at least occasionally, white, and the upper parts grizzled, and that S. bocourtii
is a grizzled brown variety, perpetuating the youthful character in its white belly
and grizzled fur, but exhibiting a tendency also in its occasionally red tail to assume
the pelage of S. ferrugmeus, and in the spreading of the white on to the head, to
put on the garb of S. finlaysoni.
The fur of the upper parts of S. siamensis is essentially annulated, but in the
younger of two type specimens the annulation is slightly more marked, and the
animal is not so rufous as in the more matured individual. In the latter, the annulation
has almost disappeared on the head and neck; and in both, the posterior half
of the tail is chestnut, without any annulation, and the under parts are similarly
coloured. Some light is thrown on these small annulated specimens by an appa