In the skull, the muzzle is longer than the longitudinal diameter of its orbit in the series of larger species (Section A); in the smaller species (Section B) the muzzle is shorter.
Their dentition presents several important characters. The series of upper molars and pre-molars form almost a straight line, both sides being almost parallel, or only slightly convergent towards the front. In the upper jaw the incisors are wanting; the canines are very large and grooved internally, and have a posterior heel. There is no gap between them and the anterior pre-molar, which last is vertically taller than the rest, and has one cusp to the outside, whereas the median and posterior have an inner cusp as well. The anterior and median molars have the inner hind cusp rudimentary, but the cingulum rises into a minute cusp, both at the fore and hind edge; the posterior molar is three-cusped. The whole of the cheek-teeth gradually broaden and decrease in vertical height from before backward as far as the median molar. In the lower jaw the anterior pre-molars are large, canine-like, and decumbent, and have a strong process on their anterior margin (resembling that in the corresponding tooth in Indris); the median and posterior pre-molars have one external cusp, and the latter tooth one interior cusp in addition. The anterior and median molars have a rudimentary fifth cusp, which is large in the posterior molar.
The pre-maxillæ are very much reduced, so that the teeth they usually carry are generally wanting. The bony palate is short, its hind margin extending back only to the middle of the median molar; its anterior foramina are small; and it differs from that of Microcebus and Chirogale in having its posterior perforations small. The angle of the lower jaw is produced downwards and backwards. The mastoid portion of the ear-capsules (periotic bones) as well as the squamosal are markedly enlarged and swollen, in this respect differing from the skulls of Lemur and Hapalemur. The ridges in the temporal bone unite into a frontal (sagittal) ridge, and the space between the orbits is depressed; a depression is also present on the cheek in front of the lachrymal foramen. The foot is slightly elongated by the lengthening of the naviculare bone of the ankle (tarsus), the thin bones of which are short. In the wrist (carpus) there is no os centrale or central bone, which is otherwise invariably present in the Primates, except in Man, the Chimpanzees, the Gentle-Lemurs, and the Endrina.
The Sportive-Lemurs are confined to Madagascar and are nocturnal and arboreal creatures, feeding on leaves and fruits.
In Group A (the larger species) are included: 1, The Weasel-like Lemur (L. mustelinus); 2, the Red-tailed Sportive-Lemur (L. ruficaudatus); 3, Edwards' Sportive-Lemur (L. edwardsi); and 4, the Small-toothed Sportive-Lemur (L. microdon). Group B (consisting of the smaller species) comprises: 1, The Round-headed Sportive-Lemur (L. globiceps); 2, Grandidier's Sportive-Lemur (L. grandidieri); and 3, the White-footed Sportive-Lemur (L. leucopus). With the exception of the two first-named species, all the others are here made known for the first time by Dr. Forsyth Major. Very little is recorded of the habits of these animals. They are so rare that at present the various species are known from a few skins or alcoholic specimens in European museums. They are said to be inhabitants only of the forest-country, nocturnal in their habits, sleeping coiled up in some retreat all day, but issuing forth at night, at which time they are very agile in their movements.
SECTION A. (SPECIES MAJORES.)
I. THE WEASEL-LIKE SPORTIVE-LEMUR. LEPIDOLEMUR MUSTELINUS.
Lepilemur mustelinus, Is. Geoffr., Cat. Méth. Primates, p. 76 (1851); Schl. et Pollen, Faun. Madag., Mammif., p. 10, pls. 4, 6, fig. 3; Schl., Mus. P. B., vii., p. 317 (1876).
Lepilemur dorsalis, Gray, Cat. Monkeys, Brit. Mus. App., p. 135 (1870).
Characters.—Fur soft and woolly; ears rounded, naked excepting at the base behind; muzzle elongated. Above, reddish-grey. Face and cheeks grey; throat white; under side of body and inner side of limbs, pale grey; tail short-haired, the posterior third dark brown. Length of body, 14 inches; and tail 10 inches.