There is only one species in this genus, the beautiful little Pigmy Flying-Phalanger (_A. pygmæus_), not so big as a Mouse, which is found in Queensland, New South Wales, and Victoria, and feeds on the honey it abstracts from flowers, and on insects. Its agility and powers of leaping are exceedingly great, and it is said by Mr. Gould to make a most charming little pet. Subfamily =Phascolarctinæ=.—Teeth large, normal; no rudimentary premolars before the last upper premolar, or any teeth between the first lower incisor and fourth premolar. Tongue of ordinary structure. Distinct cheek-pouches. Stomach with a special gland near the cardiac orifice. Cæcum very long, and (with the upper portion of the colon) dilated and provided with numerous longitudinal folds of mucous membrane. In many anatomical characters, especially the possession of a special gastric gland, this group resembles the _Phascolomyidæ_.[65] [Illustration: FIG. 49.—Skeleton of right hind foot of Koala (_Phascolarctus cinereus_), showing the stout opposable hallux, followed by two slender toes, which in the living animal are enclosed as far as the nails in a common integument.] _Phascolarctus._[66]—Dentition: _i_ ³⁄₁, _c_ ¹⁄₀, _p_ ¹⁄₁, _m_ ⁴⁄₄; total 30. Upper incisors crowded together, cylindroidal, the first much larger than the others, with a bevelled cutting edge (Fig. 36). Canine very small; a considerable interval between it and the premolar, which is as long from before backwards but not so broad as the true molars, and has a cutting edge, with a smaller parallel inner ridge. The molars slightly diminishing in size from the first to the fourth, with square crowns, each bearing four pyramidal cusps, with curved ridges radiating from them, and having a structure very similar to these of _Pseudochirus_. The lower incisors are semiproclivous, compressed and tapering, bevelled at the ends. Premolars and molars in continuous series, as in the upper jaw. Milk-tooth very minute, and almost functionless. Fore feet with the two inner toes slightly separated from and opposable to the remaining three, all with strong, curved, and much compressed claws. Hind foot (Fig. 49) with the hallux placed very far back, large and broad, the second and third (united) toes considerably smaller than the other two; the fourth the largest. No external tail. Fur dense and woolly. Ears of moderate size, thickly clothed with long hairs. Vertebræ: C 7, D 11, L 8, S 2, C 8. Ribs eleven pairs, a rare exception to the usual number (13) in the Marsupialia.