Phalangista.

Bones of animals of this group, to which the well-known "Opossums" and "Flying Squirrels" belong, are rare; the only specimens observed, two fragments of a lower jaw, indicate species allied to, or identical with, the living Vulpine Phalanger (P. vulpina), and the "Sugar Squirrel" (Belideus breviceps). The curious "Native Bear" is also a Phalanger, and forms the connecting link between the Wombats and the "Phalangers proper" (the "Opossums" and "Flying Squirrels"). All these creatures have a nailless thumb to the hind foot; they also possess, like the Kangaroo family, the two small inner toes joined by a membrane. Wombats, Phalangers, and Kangaroos (including Wallabies and Kangaroo-rats), seldom produce more than two young at a time; one at a birth is, however, the general rule. The Phalanger family comprises some of our very largest creatures, namely, the gigantic Diprotodons, Zygomaturi, and Nototheri, about the position of which there has been much discussion. Looking at the dentition, and comparing the incisors only, the observer is struck at once with their close resemblance to the teeth of an ordinary native bear. The short tail of both the "Native Bear" and "Wombat" appears to have been peculiar to the large extinct species also; though this supposition is only based on negative evidence—the absence of any caudal vertebra? of a size in proportion to the other large bones which have been found.

Diprotodon.

The collection consists of many fragments of jaws and teeth of great size, indicating ten or more species.

Zygomaturus.

This large animal is represented in our collection by two or three species,—the original Zygomaturus trilobus, the Z. Macleayi, and a still undescribed one, lately discovered by Dr. Mildred Creed, near Scone.

Nototherium.

Of the Zygomaturus we know the skull and teeth of the upper series, and of the Notothere only the lower jaw. But many of these mandibles may yet prove to be those of Zygomaturus. It will be necessary, however, to obtain clearer evidence on the subject, as, for instance, palate and jaw of the same animal found close together and properly fitting; specimens of this kind are still missing.

Thylacoleo.

This animal was first described by Professor Owen; it is evidently a Phalanger and comes close to the "Flying Squirrel" (Belideus flaviventer). The great premolar of Thylacoleo is not found in Belideus, and the grinders differ much in the two species, but the incisors above and below are of the same shape, and skull and jaw, when compared with the much larger Thylacoleo, appear to be formed on a similar model. That it was erroneous to consider the Thylacoleo a formidable carnivore, and a match for the ponderous Diprotodons, is plainly discernible from the remains (nearly perfect jaws) in our collections; many of the "trenchant" teeth are worn quite flat, the incisors are weak, and the upper ones often rounded off to conical prints, unfit to hold or tear tough substances such as flesh.

Besides these remains, others indicating a smaller allied species have come to hand.

Plectodon.

This genus is distinguished by lower incisors of a peculiar form, much shorter and more round than those of Thylacoleo; a portion of the enamel laps over, and covers the inner side of the tooth like a fold;—hence the generic term.