SCIUROMORPHA. 273 
cases where it is attached to the extremity of the tibia; the zygomatic 
arch is formed chiefly by the malar, which is not supported beneath by 
a continuation of the zygomatic process of the maxillary ; collar-bones 
perfect ; upper lip cleft; the muffle small and naked ; tail cylindrical 
and hairy (except in Castorida). Five families. 
SECTION meer OR RAT-LIKE RODENTs. 
ae 8 
© the former being the usual number ; 
the tibia and fibula are pease for at least a third of their length. The 
zygomatic arch is slender, and the malar process rarely extends so far 
forward as in the preceding section, and is generally supported below 
by a continuation of the maxillary zygomatic process ; collar bones are 
perfect (except in Lophiomyide); upper lip and muffle as in the last ; 
tail cylindrical, sometimes hairy, but commonly covered with scales 
arranged in rings. Seven families. 
Section III.—HystricoMORPHA, OR PORCUPINE-LIKE RODENTS. 
With one exception (Ctenodactylus) have four molars in each upper 
and lower jaw; the tibia and fibula are distinct in young and old ; the 
zygomatic ,arch is stout, and the malar does not advance far forward, 
nor is it supported by the maxillary zygomatic process; collar-bones 
perfect in some ; the upper lip is rarely cleft; the muffle clad with fine 
hair ; tail hairy, sub-naked or scaly. 
SecTIon I.—SCIUROMORPHA. 
Contains the following families, those that are not Indian being 
in ttalics :-— 
(1) Anomaluride ; (2) Sciuride; (3) Lschyromyide, a fossil genus ; 
(4) Haplodontide ; (s) Castorida. 
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 horny 
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 cartila- 
ginous spur starting from the elbow. 
Of the Sciuridze we have many examples in India, which will be 
noticed further on, 
T 
