paid to cranial characters seems to have been confined to the number of upper incisors. Before proceeding to a description of the species in the genus, it will be well to consider some characters of the Slow Lemurs as a whole.
PELAGE AND COLOR.
Two different types of hairs are found on the Slow Lemurs: (1) A very dense woolly crinkly coat, corresponding in general to what is known as the underfur in mammals, about 20 mm. in length, on middle of back; and (2), a set of longer hairs, much more scant than the dense woolly ones and from 5 to 10 mm. longer, being nearly straight throughout their length, slight crinkling taking place for a distance of 5 to 10 mm. along the middle. The woolly hairs are not found typically on the face, or on the hands and feet. These two sorts of hairs are not sharply defined types and many individual hairs are seen which are intermediate between the two.
The basal half or a little more of the woolly hairs is of a general slate-gray or almost plumbeous color, darker on the hairs of the back and lighter on those of the belly. Normally, this slaty color is never seen in the upper parts except on parting the thick coat, but on the underparts where the hairy covering is less dense a certain amount of the slaty or plumbeous color shows through. The distal half of the woolly hairs is about equally divided between two colors, a grayish or yellow-gray color next the slaty basal color, and terminally some sort of an ochraceous or buffy color, to which the general color of the animal is due. On the dark face marks when present and along the dorsal stripe the terminal color of the hairs is much darker, varying from a light, bright russet to a very dark brown.
The long straight hairs have little to do with the real general color effect. They seem to be very similar in color to the woolly hairs except at the tip, where there is a large white subterminal ring about 3 to 5 mm. wide. The apical ring is about 1 to 2 mm. wide and dark in color, which is not seen ordinarily and has no effect on the general color. The subterminal white ring, however, often apparently enters very largely into the general color scheme, and in case the hairs are long and their tips not worn produces a conspicuous frosting overlying the general ochraceous color of the upper parts. This frosted effect is most conspicuous in two specimens of Nycticebus malaianus, a two-thirds grown individual, Cat. No. 84390, U. S. N. M., from Trong, Lower Siam; and a young adult male, Cat. No. 114151, U. S. N. M., from Johore Lama. In an adult of unknown sex, Cat. No. 84389, U. S. N. M., from Trong, no frosting at all is present except a very slight amount on the upper part of the neck. Except for a few hairs on either side of the dark median stripe no frosting is seen in Cat. No. 142233, U. S. N. M., a young adult male from western Borneo. An adult male, Cat. No. 142234, U. S. N. M., also from western Borneo, shows nearly
