339 
PETAUEUS (. Acrobata ) PYGMiEUS. 
Pigmy Plying-Opossum. 
Didelphispygmcea. Shaw, Zoology of New Holland, No. 1, 
PI. 2, p. 5, 1794.—General Zoology, 
vol. i. Pfc. 2, p. 501. 
Petaurus pygmanis. Desmarest, Nouv. Diet. d’Hist. Nat. 
tom. xxv. p. 405. 1818. 
Petaurista (Acrobata) pygmcea. Desm. Mammalogic, Pt. 1, p. 270. 1820. 
Petaurus (Acrobata) pygmeeus. Waterhouse, Marsupialia, p. 293, PI. 30. 
Fur rather short anil soft ; on the upper parts of the body of an 
ashy grey brown colour, and on the under parts, white, or 
yellowish white: ear with a dusky patch in front externally, 
and whitish behind: tail ashy brown, paler below than above: 
eye encircled with black. 
Inhabits New South Wales. 
This pretty little animal, wliich is the “ Opossum Mouse ” 
of the colonists of New South Wales, is said to be exceed¬ 
ingly numerous in the vicinity of Port Jackson. It is about 
the size of the Common Mouse, and of an ashy brown colour, 
inclining to grey, on the upper parts of the body, flank mem- 
thc groups exhibiting those affinities. In the present case we have an instance, 
on the one hand, of two species of Phalangislidce of different genera, approxi¬ 
mating very closely ; and, on the other hand, of a species of the family Phalan- 
gistidcc approaching to certain Dasyuridce. Now, the approximation of the 
species of the two genera of the same family, is much closer than that evinced 
by the Acrobata to the Phascogale (these being of different families), inasmuch 
as the resemblance in the latter case is only in the dentition, and that but 
partial, since the structure of the molar and incisor teeth in Acrobata is in 
accordance with the Phalangista type, and unlike that of the Phascogales; and, in 
the conformation of the extremities, I can perceive no tendency on the part of 
Acrobata to assume the characteristics of the Dasyuridce; the second and 
third toes of the hind foot are not less perfectly united in Acrobata than in 
other Phalangistidce. 
