_Prosimia_, Brisson, Regn. Anim., p. 220 (1756).
_Lemur_, Linn., Syst. Nat., i., p. 44 (1766).
_Varecia_, Gray, P. Z. S., 1863, p. 135.
This genus contains the typical Lemurs, in their most restricted sense.
They are characterised by having a very {66}Fox-like head, and an elongate
and tapering face, shelving on each side of the nose. A long fringe of hair
surrounds their chin and cheeks. They have all large and tufted ears, and
large eyes, with superciliary ridges rising higher than the forehead. Their
tail is always half as long as the body at least. The fore-limbs are
somewhat shorter than the hind-limbs, and both the wrist and ankles are
haired. The ankle is not elongated, nor is the great toe as large as in the
next family--the _Indrisinæ_. On the outside of the palm of the hand and
under the base of the fingers are situated fleshy pads, giving them greater
grasping power. The True Lemurs have only one pair of mammæ, which are
situated on the breast.
In the skull the facial region is much elongated, its measurement from the
anterior margin of the orbit forward being greater than the longitudinal
diameter of the orbit, and the space between the eye-sockets is narrow and
depressed. The bony palate is short, extending back only to the posterior
end of the median molar. The posterior portion of the ear-capsules (the
mastoidal and squamosal regions) is not inflated--a character which
separates this genus from _Galago_. The pre-maxillary bones are large and
protrude in front, if the skull be viewed from the side. The angle of the
lower jaw is not produced downwards and backwards. In some species a large
maxillary sinus projects into the anterior part of the orbit; in some also
the _foramen rotundum_ does not coalesce with the sphenoidal fissure (see
page 11), but has a distinct opening. The teeth are of the normal number,
namely thirty-six. In the upper jaw the incisors are small, sub-equal, and
situated anteriorly to the canines and are not in contact with each other,
or with the latter. The canines are very large, tusk-like, and set in an
excavated notch on the jaw. All the pre-molars {67}have one main cusp to
the outside; the anterior pre-molar, however, has a supplementary minute
front cusp, while the median has in addition one large interior cusp; both
it and the posterior pre-molars are vertically taller than their anterior
fellow. The molars have two inner cusps, and two main outer cusps with a
supplementary minute fore cusp, as well as two cusps on the ridge joining
the fore and hind outer cusps; the posterior molar--the smallest of the
three--is, however, larger than the posterior pre-molar, and has only the
front inner cusp and no supplementary external cusp. The lower jaw shows a
gap between the canine and the anterior pre-molar. The anterior pre-molar,
which is vertically taller than the rest, is edged and cutting, taking the
place of a tusk; the anterior and median pre-molars are also separated by a
small space; the latter, which is equal in vertical height to the
posterior, has an inner cusp and a low cusped heel. The molars have two
outer main cusps, of which the front one is more developed than the hind
one, and two inner cusps, often with an intermediate cusp between them; the
pair of fore and the pair of hind cusps are joined by transverse ridges,
and the two outside cusps by a backwardly directed semicircular ridge; the
posterior molar is four-cusped.
The dorsal and lumbar vertebræ together do not exceed twenty in number.
The hind portion of the cerebellum is large, which points to intellectual
inferiority in the True Lemurs as compared with the Apes.
The species of this genus are all confined to the island of Madagascar and
some of the smaller adjacent islands. They are gregarious, living in large
companies in the forests, feeding on fruits, insects, and such small
animals, birds, and lizards {68}as they may capture. Like the Howlers of S.
America and the Gibbons of the East Indies, they are very noisy. Their
agility is wonderfully great, and is displayed chiefly in the evening.
During the brighter hours of the day they sit somnolent, either alone with
their heads buried between their arms, their tail coiled round the neck, or
in twos or threes embracing each other with their arms. In walking they use
their fore-limbs less as hands, and more as feet than do the members of the
next family--the _Indrisinæ_--both when on the ground, as well as when
climbing among the trees.