This early account forms the first mention of any of the numerous marsupials of the eastern hemisphere, as there can be no doubt that the animal called the cousa by the natives of Amboyna nearly 300 years ago was the Grey Cuscus (Cuscus orientalis}, a member of the only marsupial genus occurring in any Eastern land then known to Europeans. About a hundred years afterwards the same animal was seen by the Dutch traveller Valentyn, also at Amboyna, and still later Buffon gave to a pair of cuscuses examined by him the name that heads this article, “Phalanger,” on account of the peculiar structure of the second and third toes of the hind feet, which are united in a common skin up to the nails, a character now known to be present in a large proportion of the Australian marsupials. Later, Captain Cook in 1770 and 1777, Governor Phillip in 1788, and J. White in 1790 discovered various different kinds of phalangers, and now we know of not less than ten genera, with about thirty-five species, forming the sub-family Phalangistinae of the family Phalangistidae, whose general characters have already been noticed in the article Mammalia (vol. XV. p. 382).

Phalangers as a whole are small woolly-coated animals, with long, powerful, and often prehensile tails, large claws, and, as in the American opossums, with opposable nailless great toes. Their expression seems in the day to be dull and sleepy, but by night they appear to decidedly greater advantage. They live mostly upon fruit, leaves, and blossoms, although some few feed habitually upon insects, and all relish, when in confinement, an occasional bird or other small animal. Several of the phalangers possess flying membranes stretched between their fore and hind limbs, by the help of which they can make long and sustained leaps through the air, like the flying squirrels; but it is interesting to notice that the possession of these flying membranes does not seem to be any indication of special affinity, the characters of the skull and teeth sharply dividing the flying forms, and uniting them with other species of the non-flying groups. Their skulls (see fig. 1) are as a rule broad and flattened, with the posterior part swollen out laterally, owing to the numerous air-cells situated in the substance of the squamosals. The dental formula is very variable, especially as regards the premolars, of which some at least in each genus are reduced to mere functionless rudiments, and may even vary in number on the two sides of the jaw of the same individual. The incisors are always ®, the lower one very large and proclivous, and the canines normally ⅜, of which the inferior is always minute, and in one genus generally absent. The true molars number either ± or ⅜.

The genera, of which not less than ten must be allowed as valid, may be arranged as follows. [table]

1. Phalangista, Cuv.

Upper incisors forming a semicircular series. Upper i. 1 scarcely larger than the others, parallel, its anterior surface flattened, point transversely truncated. Canines some way from and shorter than incisors, in front of the premaxillary-maxillary suture. a Pm. 1 small, some way separated both from canine and pm. 3 ; pm. 2 suppressed; pm. 3 large, obliquely placed. Molars large, quadrangular, their summits with distinct crescentic ridges. Lower incisors large; canines very small, but persistent; pm. 1 and pm. 2 small, or, commonly, absent; pm. 3 large and obliquely placed; molars like the upper ones.

Dental formula b—i⅛⅜ c.ì pm. m. H'j 4 × 2 = 34 to 38.

Skull low, without frontal sinuses; bullae scarcely inflated; premaxillary long; the anterior palatine foramina almost confined to the premaxillae; mandible with no trace of an external opening into the inferior dental canal.

Feet normal; tail long and bushy, only naked for a few inches along the under-side of the tip.

Range.— The whole of Australia and Tasmania; not yet found in New Guinea.

This genus, by its somewhat elongated premaxillae, restriction of the palatine foramina to the latter bones, and by the shape of its upper pm. 3 , shows a certain tendency towards the kangaroos {Macropodidae), the family to which the Phalangistidae are undoubtedly most nearly allied.

The true ρhalangers, or opossums as they are called by the Australian colonists, consist of four or five hardly separable species, of which the best known is the Vulpine Phalanger {Ph. vulpecula), so common in zoological gardens, where, however, it is seldom seen, owing to its nocturnal habits. It is of about the size and general build of a small fox, whence its name; its colour is grey, with a yellowish white belly, white ears, and a black tail. It is a native of the greater part of the continent of Australia, but is replaced in Tasmania by the closely allied Brown Phalanger {Ph. /uliginosa). Its habits are very similar to those of the Yellow-bellied Flying-Phalanger {Petaurus australis) described below,—except that, of course, it is unable to take the wonderful flying leaps so characteristic of that animal. Like all the other phalangers, its flesh is freely eaten both by the natives and by the lower class of settlers.

2. Cuscus, Lacép.

Upper incisor row angular in front. Upper i. 1 considerably longer than the others, round, pointed. Canines close against the last incisors, longer than any of the other teeth, placed apparently on the suture. Pm. 1 well developed; pm. 2 minute or absent; pm. 3 large, rounded, its axis slightly oblique. Molars and all the lower teeth much as in Phalangista, but rather larger in proportion.

Ί 9 Q ί ]2*Q 1 9 Q 4

Dental formula.— i. c. τ pm. 1 <⅛r∣ m. 1 ' 2 ' 3 ~j × 2 = 34 to 40.

Frontal region of skull in adult animals markedly convex, owing to the presence of large frontal sinuses; bullae not inflated; premaxillary bones very short; palatine foramen entering the maxillae; no external opening into the inferior dental canal.

Feet normal; tail long, naked and scaly for its terminal two-thirds, prehensile.

Range.— From Celebes to the Solomon Islands, and southwards through New Guinea to North Queensland.

The cuscuses are curious sleepy-looking animals, which inhabit the various islands of the East Indian archipelago as far west as Celebes, being the only marsupials found west of New Guinea. As already noted, it was a member of this genus, the Grey Cuscus {C. orientalis), a native of Amboyna, Timor, and the neighbouring islands, which was the first Australian marsupial known to European naturalists. There are altogether about eight species known, all of about the size of a large cat; their habits resemble those of other phalangers, except that they are said to be somewhat more carnivorous.

3. Pseudoehirus, Ogilb.

Upper incisor row angular. First upper incisor but little longer than the others, but nevertheless the longest tooth in the jaw. Canine small, behind suture. Pm. 1 rather small; pm. 2 and pm. 3 larger, each with two roots, neither placed at all obliquely. Molars quadrangular, with very distinct crescentic ridges; all the teeth from the incisors backwards forming a nearly continuous series. Lower pm. 3 only forming part of the molar series.

Dentalformula.— 1. —θ c.- r pm. yr⅛~ 3 m ∙ 1 2 3 . × 2 = 36 to 40.

Skull without frontal sinuses; palatine foramina entering maxillae, as in all the following genera except Daetylopsila ; bullae inflated; palate generally complete; a minute external opening into the inferior dental canal generally present in the position of the large vacuity characteristic of the Macropodidae.

Ears large; fore-feet with the first two toes together opposable to the remaining three; tail thinly-haired, prehensile.

Range.— Tasmania, Australia, and New Guinea.

There are about four species of this genus known, of which the commonest is Cook’s Ring-tailed Phalanger {Pseτιdoehiηιs eaudi∙ volvulus), an animal discovered by Captain Cook during his first voyage, at Endeavour river, North Queensland.

4. Petaurista, Desm.

Teeth almost exactly as in Pseudoehirus, except that the lower canine is generally absent, as well as the minute first and second premolars.

rι , 7 , 7 . 1.2.3 1 1.2.3 1.2.3.4 o β . . . n Dental formula.— 1. j- 0 - 0 c. p pm. 1 . ii . 3 m. 3 ^ × 2 = 34 to 40.

Bullae inflated, but small; palate generally incomplete from the level of the second molar; a distinct external opening into the inferior dental canal.

Sides of the body with a broad flying membrane stretching from the elbow to just below the knee; ears large and hairy; claws-long and sharp; tail bushy, round, and non-prehensile.

Habitat.— New South Wales.

The only species belonging to this genus is the large black Taguan Flying Phalanger {P. volans), an animal very similar to certain of the large Indian flying squirrels, and which fully agrees in its habits with the Yellow-bellied Flying-Phalanger described below. In its affinities it seems to be, so to speak, a highly-specialized Pseudochirus, in which the teeth have become somewhat further diminished and the flying membrane has been developed.

5. Dactylopsila, Gray.

Upper i. 1 very long, directed forwards. Canine shorter than i. 3 , close to it. Pm. 2 minute or absent; pm. 3 oval, in line with molars. Molars square-sided, forming a straight line, the third as long as the second. All lower premolars small and deciduous.

.12 3 1 1 . 2 *.3 1.2.3.4

Dented formula, i. i θ θ c. y pm. 2* 3* m. 2234 ~ , ^ j

Palatal foramen in premaxilla; palate complete; bullae small; no external opening into inferior dental canal.

Form normal; fourth fore-toe very much longer than the others; tail bushy, rounded.

Range.— From the Aru Islands through New Guinea to North Queensland.

Of this genus two closely-allied species are described. They are beautifully striped down the back with white and grey, and are said to be insectivorous in their habits.

6. Petaurus, Shaw.

Upper i. 1 very long, directed downwards. Canine intermediate in length between i. 1 and i. 2 Pm. 2 the smallest, but yet functional. Molars much rounded, as are those of all the succeeding genera; m. 3 much smaller than m. 2 Lower premolars, though small, yet permanent and forming an uninterrupted series.

τ , ± . , 7 . 1.2.3 1 1.2.3 1.2.3.4 o . n Dental formula.— 1. j- y -θ c. τ pm. m. 1 2 3 4 × 2 = 40.

Palatal foramen entering maxilla; bullae inflated; a small external opening into the inferior dental canal.

Sides of body with a flying membrane stretching from the outside of the tip of the anterior fifth toe to the ankle; tail bushy; ears large and nearly naked.

Range.— From New Ireland to South Australia, but not Tasmania.

This genus contains about five species, the largest of which is the Yellow-bellied Flying-Phalanger {P. australis), whose habits are recorded by Mr Gould as follows. “This animal is common in all the brushes of New South ΛVales, particularly those which stretch along the coast from Port Philip to Moreton Bay. In these vast forests trees of one kind or another are perpetually flowering, and thus offer a never-failing supply of the blossoms upon which it feeds; the flowers of the various kinds of gums, some of which are of great magnitude, are the principal favourites. Like the rest of the genus, it is nocturnal in its habits, dwelling in holes and in the spouts of the larger branches during the day, and displaying the greatest activity at night while running over the small leafy branches, frequently even to their very extremities, in search of insects and the honey of the newly-opened blossoms. Its structure being ill adapted for terrestrial habits, it seldom descends to the ground except for the purpose of passing to a tree too distant to be attained by springing from the one it wishes to leave. The tops of the trees are traversed by this animal with as much ease as the most level ground is by such as are destined for terra firma. If chased or forced to flight it ascends to the highest branch and performs the most enormous leaps, sweeping from tree to tree with wonderful address; a slight elevation gives its body an impetus which with the expansion of its membrane enables it to pass to a considerable distance, always ascending a little at the extremity of the leap; by this ascent the animal is prevented from receiving the shock which it would otherwise sustain.”

A second species, P. sciureus, in some ways one of the most beautiful of all mammals, has been chosen for the accompanying cut∙(see fig. 2).

7. Gymnobelideus, Μ‘Coy.

Like Petaurus in every respect, but without any trace of a flying membrane.

Habitat. — V ictoria.

8. Dromicia, Gray.

First upper incisor and canine very long. Pm. 1 and pm. 2 very minute; pm. 3 large. Molars rounded; their series bowed inwards. Lower canine and first two premolars very small but persistent; pm. 3 either large and functional or minute.

123 1 l*2*3 123

Dental formula.— i. p y0 c. γ pm. 12 ' 3 W m. ~- 3 × 2 = 32 to 36. Palate incomplete; bullae very large and inflated.

No flying membrane; claws short, exceeded in length by the pads under them; toes subequal; tail thinly haired, prehensile.

Five species of Dormouse Phalangers are recorded, ranging from New Guinea to Tasmania.

9. Distoechwrus, Peters.

Upper teeth much as in Acrobata, but pm. 3 reduced, shorter than molars, and crowded obliquely out of the molar series. Lower teeth also as in Acrobata, but pm. 3 is entirely suppressed.

7 -, , 7 , 7 . 1.2.3 1 1.2.3 1.2.3 o o .

Dental formula.— 1. 1 ~ y -θ c. ∙ 5 - pm. 1 -γθ m. × 2 = 34. Skull as in Acrobata.

No flying membrane; tail distichous; ears very short; claws well developed.

Habitat.— New Guinea only, whence a single species is known. 10. Acrobata, Desm.

Upper i. 1 long. Canine proportionally more developed than in any other phalanger, pressed close against last incisor. Premolars all long, narrow, sharply pointed, and two-rooted. Lower pm. 1 minute, but always present; pm. 2 and pm. 3 functional, shaped like the upper ones.

Dental formula.— 1. c. — pm. j- 23 m. j-y 3 ×2 = 36.

Palate incomplete; bullae low and small; palatal foramen nearly all in the maxillary; a well-marked external opening into the inferior dental canal; squamosals but little swollen by air-cells.

A flying membrane present, stretching from the elbow to the knee, but very narroλv in its centre; tail distichous, probably slightly prehensile; toes subequal; claws small and far surpassed by the very remarkable toe-pads, which are broad and ribbed, resembling those of a gecko, and evidently have a very definite adhesive power.

Range.— South and eastern Australia.

There is only one species in this genus, the beautiful little Pigmy Flying-Phalanger, not so big as a mouse, which feeds on the honey it can abstract 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. (0. T,)