The Lemurs comprised in the present Sub-family are divisible into two groups--those inhabiting the mainland of Africa and those confined to the island of Madagascar. The exclusively African species, the True Galagos, constitute the single genus _Galago_; while the Malagasy group is represented by three genera, the so-called Fat-tailed Lemurs (_Opolemur_), the Dwarf-Lemurs (_Microcebus_), and the Mouse-Lemurs (_Chirogale_). The members of this Sub-family vary considerably in size, and are all covered with soft woolly fur. Their ears especially are largely developed, being more or less membranaceous and naked, and their sense of hearing very acute. The eyes are large and the tail always elongated. In the skull the length of the muzzle is less that the greatest longitudinal diameter of the orbit (except in the genus _Galago_). {38}Their teeth number 36--18 above and 18 below--as in the bulk of the _Lemuridæ_; the upper molars present on their crown an oblique ridge from the outer hind cusp to the inner front cusp. The ankle region (_tarsus_) of the hind-limb is much elongated, through the lengthening of two of its bones (the _calcaneum_ and _naviculare_): this feature occurring to a greater extent among the African than among the Malagasy species. The mammæ are four in number, two on the breast and two on the abdomen. Many of the species hibernate during the dry winter season, and to enable them to survive, they accumulate during the summer months a thick deposit of fat over their bodies, more especially at the root of the tail, a fact first conspicuously observed in the Opolemurids. This fat is absorbed for their sustenance during their prolonged torpidity. THE AFRICAN GALAGOS. GENUS GALAGO. _Galago_, Geoffr., Mag. Encycl., Ann. 2, i., p. 49 (1796). The African Galagos are generally larger in size than the Madagascar members of the group, and have the snout produced beyond the lower jaw. Their ears are large, membranaceous, and have a very mobile contractile hinder edge, the animal having the power of folding them up at will. The eyes are also large and approximated; the fingers and toes very long and slender, and the tail thick and bushy. The skull presents a high, broad, and round brain-case, with a relatively short facial region. The pre-maxillary bones are very much reduced, so that the muzzle, measured from the anterior margin of the orbit forward, is shorter than the longitudinal diameter of the orbits. The bony palate is also relatively short. Compared with those of the Madagascar genera {39}the orbits are, according to Dr. Forsyth Major, much broader vertically and horizontally in the genus _Galago_. The squamosal region of the skull and the outer portion of the ear-capsules (the periotic) are large and inflated. The mandible (or lower jaw) has its lower hind edge, or angle, produced backward.