Dentition: _i_ ⁴⁄₃, _c_ ¹⁄₁, _p_ and _m_ numerous, variable. Incisors small; canines well developed; molars with pointed cusps. Limbs equal. Fore feet with five subequal toes terminating in claws. Hind feet with the four outer toes well developed, and distinct from each other and bearing claws; the first (or hallux) clawless, generally rudimentary, sometimes entirely wanting. Stomach simple. No cæcum. Predatory carnivorous or insectivorous animals, inhabitants of Australia, Tasmania, and the southern parts of New Guinea and some of the adjacent islands. The aberrant genus _Myrmecobius_, though clearly a member of this family, is so sharply distinguished from all the others as to render a division into two subfamilies necessary. [Illustration: FIG. 39.—The Thylacine (_Thylacinus cynocephalus_).] Subfamily =Dasyurinæ=.—This comprises the more typical _Dasyuridæ_, in which the premolars and molars never exceed the normal number of seven on either side of each jaw, and in which the tongue is not specially extensile. _Thylacinus._[42]—Dentition: _i_ ⁴⁄₃, _c_ ¹⁄₁, _p_ ³⁄₃, _m_ ⁴⁄₄ = 46. Incisors small, vertical, the outer one in the upper jaw larger than the others. Summits of the lower incisors, before they are worn, with a deep transverse groove dividing them into an anterior and a posterior cusp. Canines long, strong, and conical. Premolars separated from one another by intervals, with compressed crowns, increasing in size from before backwards. True molars in general characters resembling those of _Dasyurus_, but of more simple form, the cusps being not so distinct nor sharply pointed. Milk-molar very small, and shed before the animal leaves the mother’s pouch. Humerus with an entepicondylar foramen. General form very Dog-like. Head elongated. Muzzle pointed. Ears moderate, erect, triangular. Fur short and closely applied to the skin. Tail of moderate length, thick at the base and tapering towards the apex, clothed with short hair. Hallux (including the metacarpal bone) wanting. Vertebræ: C 7, D 13, L 6, S 2, C 23. Marsupial bones represented only by small unossified fibro-cartilages.