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.

Macropodidæ.

Numerous species of all sizes, some several times larger than any modern Kangaroo, existed in Australia in former ages, but their remains are much scattered about, and upper and lower jaws are seldom found together; to distinguish the bones as those of particular species is out of the question, and we must content page 20 ourselves at present to class them as Kangaroo, or Kangaroo-rat bones. The fossils which resemble, or are identical with, modern species, may of course be more correctly classified.

As a general rule, most of the fossil Kangaroos have shorter and stouter tarsi than living species possess, and the greater number, including the largest of the tribe, must be arranged with the Halmaturi or Wallabies, a group of Kangaroos with permanent and often large premolar teeth.

The Kangaroos proper, of which our common Great Kangaroo is the type, soon shed their premolars, and continue to lose the grinders also in such a manner that sometimes only a pair of teeth are left in each ramus. The Wallabies, on the other hand, wear the teeth down. Looking at a Kangaroo's incisors, we find the first of the upper series comparatively small, and the third very broad; whilst the Wallabies have the third tooth large in a vertical direction, and in most species this tooth is deeply indented by a fold.

In all recent Kangaroos, Wallabies, and Kangaroo-rats, the rami of the lower jaw are movable; in many fossil Kangaroos this peculiar characteristic is wanting, and the two mandibles are firmly anchylosed, as may be observed in the two fossil species Halmaturus Scottii and Halmaturus Thomsonii.

The premolars of the fossil species are often very bulky, with a deep hollow in the middle of the tooth—another characteristic peculiar to extinct animals of this tribe.

The following genera belong to the family Macropodidæ:—

Bettongia.

Comprising the Kangaroo-rats, or more correctly speaking, the "Bettongs," with long hind legs, and more or less prehensile tail. Of these animals many remains were found at Wellington, all of which appear to be identical with the common Bettong Bettongia rufescens, now living in New South Wales.

Hypsiprymnus.

This genus had very few representatives, and comprises the smaller Kangaroo-rats, with short stiff tails and short hind-legs; all Hypsiprymni progress in the same manner as the Bandicoots.

Macropus.

The typical species is our Macropus major or Great Kangaroo. Fossil remains of closely allied species, and of others, resembling M. ocydromus, M. rufus, and M. robustus, are in our collection.

Halmaturus.

This genus, distinguished by permanent and often very large premolar teeth, is numerously represented in a fossil state, and cannot be estimated at less than thirty or more species; the Wombat-like Kangaroos, with short anchylosed jaws, are here included.

Dasyuridæ.

The rich deposits in the Caves of Wellington have supplied us with evidence of the existence of two species of "Native-cats," that is, a common Dasyurus viverrinus, and a "Tiger-cat," Dasyurus maculatus; besides these small carnivores we have to record the presence in post-tertiary Australia of the formidable Sarcophilus vrsinus, the "Tasmanian Devil," and the still more ferocious Thylacinus cynocephalus, Thylacine or "Tasmanian Tiger." The number of teeth belonging to these creatures, collected at the Wellington Caves, amount to several hundred; other remains (skulls and jaws) are as plentiful, and many of their owners must have died at a ripe old age, because their canine teeth are often worn level with the rest of the series.

Phascogale, Antechinus, and Podabrus.

These small animals represent the Shrews and Hedge-hogs of the Placental division. The difficulty of discovering their remains is very great, a tiny jaw, less than ? of an inch in length, proves the existence in post-pleiocene Australia of mammals not larger than a small mouse.