Part 50 (2/2)

SECTION I.--SCIUROMORPHA.

Contains the following families, those that are not Indian being in italics;--

(1) _Anomaluridae_; (2) Sciuridae; (3) _Ischyromyidae_, a fossil genus; (4) _Haplodontidae_; (5) _Castoridae_.

The Anomalures are African animals resembling our flying squirrels, to which they were at first thought to belong, but were separated and named by Mr. Waterhouse, the chief peculiarity being the tail, which is long and well covered with hair, though not bushy as in the squirrels, and which has, at its basal portion, a double series of projecting h.o.r.n.y scales, which probably help it in climbing trees.

There are several other peculiarities, which I need not dwell on here, which have justified its separation from the true squirrels. The flying membrane, which is quite as large as that of the flying squirrels, extends from the elbow to the heel instead of from the wrist, and it is held out by a strong cartilaginous spur starting from the elbow.

Of the Sciuridae we have many examples in India, which will be noticed further on.

The _Ischyromyidae_ is founded on a single North American fossil genus (_Ischyromys typus_), which is nearly allied to the Sciuridae, but also shows some affinity to the beavers.

The _Haplodontidae_ is also an American family, founded on one genus, but an existing and not a fossil animal. The _Haplodon rufus_ is a small burrowing rodent, valued by the Indians both for its flesh and its skin, of which from twenty to thirty are sewn together to form a robe; the teeth are rootless, simple, and prismatic, the surface of each being surrounded by a mere border of enamel.

The _Castoridae_ is the beaver family, which is also unknown in India.

Unlike as this animal is externally to the squirrels, its anatomy warrants its position in the Sciuromorpha, otherwise one would feel inclined to include it in the next section.

We see that of the five families, of which this section is composed, only the second has its representatives in India.

SCIURIDAE--THE SQUIRRELS.

This family contains the true squirrels, including the flying ones, and the marmots. The distinctive characteristics of the former are as follows: The gnawing teeth are smooth, compressed. The grinding teeth are 5--5/4--4 or 4--4/4--4; in the former case the first upper premolar is small, and sometimes deciduous; they are tubercular, at least in youth, and rooted. Skull with distinct post-orbital processes; infra-orbital opening small, usually placed in front of the maxillary zygomatic process; palate broad and flat; twelve or thirteen pairs of ribs; tail cylindrical and bushy; feet either pentadactylous or with a tubercle in place of a thumb on the fore-feet.

Mostly quite arboreal.

_GENUS SCIURUS_.

Premolars, 2--2/1--1; molars, 3--3/3--3; gnawing teeth smooth, orange-coloured, or brown; no cheek pouches; mammae three or four pairs; first upper premolar soon lost in many cases; limbs free; form agile; tail long and very bushy.

Jerdon states that ”there are three well marked groups in India distinguished by size, coloration and habits,” by which he means the large forest squirrels, the medium size grizzled ones, and the little striped squirrels, to which however I must add one more form, which is found out of the geographical limits a.s.signed to his work--the _Rhinosciurus_, or long-snouted squirrel, an animal singularly like a Tupaia. The squirrels, as a whole, form a natural and well-defined group, with a remarkable uniformity of dent.i.tion and skull, but of infinite variation in colour. In fact, it is most puzzling and misleading to find so great a diversity of pelage as is exhibited by a single species. I was shown by a friend a few months ago a fine range of colours in skins of a single species from Burmah--_S.

caniceps_. I cannot attempt to describe them from memory, but the diversity was so marked that I believe they would have been taken by unscientific observers for so many different species. Now in domesticated animals there is great variation in colouring, but not in the majority of wild species. What the causes are that operate in the painting of the skin of an animal no one can say, any more than one can say how particular spots are arranged on the petal of a flower or the wing of a b.u.t.terfly. That specific liveries have been designed by an all-wise Creator for purposes of recognition I have no doubt, as well as for purposes of deception and protection--in the former case to keep certain breeds pure, and in the latter to protect animals from attack by enabling them better to hide themselves, as we see in the case of those birds and quadrupeds which inhabit exposed cold countries turning white in winter, and in the mottled skin of the Galeopithicus, which is hardly discernible from the rough bark of the tree to which it clings. I have hardly ever noticed such varied hues in any wild animals, although the _Viverridae_ are somewhat erratic in colouring, as in the Indian squirrels, and it is doubtful whether several recorded species are not so nearly allied as to be in fact properly but one and the same.

There is much in common in at least five species of Burmese squirrels, and it is open to question whether _S. caniceps_ and _S. Blanfordii_ are not the same. Dr. Anderson writes: ”I have examined a very extensive series of squirrels belonging to the various forms above described, viz., _S. pygerythrus_, _S. caniceps_, _S. Phayrei_ and _S. Blanfordii_, and of others which appears to indicate at least, if not to prove, that all of them are in some way related to each other.” In another place he says: ”The skull of an adult male, _S.

caniceps_, which had the bright red golden colour of the back well developed, presents so strong a resemblance to the skull of _S.

Blanfordii_, that it is extremely difficult to seize on any point wherein they differ.” After comparison of the above with skulls of _S. griseima.n.u.s_ and _S. Phayrei_, he adds: ”such facts taken in conjunction with those mentioned under _S. Blanfordii_, suggest that there is a very intimate connection between all of these forms, if they do not ultimately prove to be identical” ('Anat. and Zool.

Researches,' pp. 229, 231).

[Ill.u.s.tration: Skull of _Pteromys_ (Flying Squirrel).]

Blyth also, speaking of the larger squirrels, says: ”It is difficult to conceive of the whole series as other than permanent varieties of one species; and the same remark applies to the races of _Pteromys_, and at least to some of those of _Sciuropterus_, as also to various named _Sciuri_” ('Cat. Mam.,' p. 98).

The large forest squirrels come first on our list. They inhabit lofty tree jungle, making their nests on the tops of the tallest trees.

They are most active in their habits, and are strictly arboreal, being awkward on the ground. When kept as pets they become very tame, though some are crotchety tempered, and bite severely.

NO. 273. SCIURUS INDICUS.

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