Another kind, with a yellow flank membrane, is short-headed, and it inhabits Port Essington, North Australia,[106] whilst the true Short-headed Flying Phalanger is found in New South Wales.[107] Probably it is the first of these which is found in New Guinea, and which has been called the Squirrel Flying Phalanger by mistake. These Flying Phalangers all have long and nearly naked ears, and the side membrane extends to the outer finger. They have the outer two fingers of the hand long and equal to each other, or very nearly so; the second and third fingers are distinctly shorter than these; and the inner finger is very short. Their dentition is--Incisors, (6/2); canines, (1-1)/(0-0); premolars, (3-3)/(4-4); true molars, (4-4)/(4-4) = 40. The incisors of the lower jaw are, as usual, long and pointed, and almost horizontal, whilst the upper incisors are large and dilated, so far as the anterior ones are concerned, and the next is smaller than the hindmost. The canine is large, and separated from the first premolar, which is large and compressed, and all the molars have rounded tubercles on them. [Illustration: SQUIRREL FLYING PHALANGER.] The OPOSSUM MOUSE[108] of the colonists of New South Wales used to be common in the neighbourhood of Port Jackson. It is about the size of a common Mouse, and of an ashy brown and grey colour on the upper parts and on the flank membrane; the rest is white. It belongs to the Flying Phalangers, but its side membrane scarcely extends to the wrist, and the thumb of the hind foot is large. It has only three true molars in each jaw on both sides, and the canine is close to the incisors. It forms part of the sub-genus Acrobata, whilst those already mentioned constitute the sub-genus Belideus (βέλος, a dart). Finally, the short-eared, white-bellied Taguan Phalanger of the scrub of New South Wales is the type of the sub-genus _Petaurus_. GENUS TARSIPES.--THE NOOLBENGER, OR TAIT.[109]