The only known existing species of this genus, _T. cynocephalus_ (Fig. 39), though smaller than a common Wolf, is the largest predaceous Marsupial at present living. It is now entirely confined to the island of Tasmania, although fragments of bones and teeth found in caves afford evidence that a closely allied species once inhabited the Australian mainland. The general colour of the Thylacine is grayish brown, but it has a series of transverse black bands on the hinder part of the back and loins, whence the name of “Tiger” frequently applied to it by the colonists. It is also called “Wolf,” and sometimes, though less appropriately, “Hyæna.” Owing to the havoc it commits among the sheepfolds, it has been nearly exterminated in all the more settled parts of Tasmania, but still finds shelter in the almost impenetrable rocky glens of the more mountainous regions of the island. The female produces four young at a time. The pouch opens backwardly, and there are four mammæ. The figure of the skull exhibits the peculiar Dog-like form so characteristic of the genus. [Illustration: FIG. 40.—Right lateral aspect of the skull of the Thylacine.] _Sarcophilus._[43]—Dentition: _i_ ⁴⁄₃, _c_ ¹⁄₁, _p_ ²⁄₂, _m_ ⁴⁄₄. Upper incisors nearly equal, and placed vertically, the first not differentiated from the rest. Premolars rounded and closely crowded between the canine and molars, with broad crowns; molars broad and heavy, the last one without a distinct hind talon. Form thick and powerful; head disproportionately large for the body; muzzle short and broad; ears broad and rounded; tail of moderate length, and evenly hairy. Hallux wanting; soles of feet naked, without defined pads. Humerus with entepicondylar foramen. This genus is now represented only by a single species (_S. ursinus_) found in Tasmania, where, from its ferocious and destructive habits, it is commonly known under the name of the “Devil.” A front view of the skull is shown in Fig. 35. The prevailing colour of this animal is black, and the size about equal to that of an English Badger; its habits are fossorial, and it is very destructive to sheep. On account of the similarity in the number of its teeth this genus has been generally included in the next one, but in the structure of the teeth it is much nearer to _Thylacinus_. An extinct species is found in the Pleistocene deposits of the mainland of Australia. It may be observed that the two premolars missing from the typical series of four in this and the next genus are the second and the fourth; the fourth milk-molar being likewise absent. In _Thylacinus_ and other Polyprotodonts with three premolars it is the second that is missing.