570 
FOSSIL MARSUPIAL ALLIED TO PETAURUS. 
The following are some of the principal measurements :- 
Lower jaw. 
Length of lower jaw from 
front of incisor to 
condyle 23*2 mm. 
Depth behind rm* 3 '3 
Depth behind m 1 3 8 ,, 
Lower molars 6 '3 ,. 
Incisor 5* ,, 
Incisor to m 4 13' ,, 
Upper jaw. 
Canine, height about l'l mm. 
ant. post, length about... 11 
1st premolar, height "8 
ant. post, length *9 
3rd premolar, height *4 
ant. post, length 1' 
4th premolar, height 1 "2 
ant. post, length 1*6 
1st molar, ant. post, length 1*8 
2nd molar, ditto 1*7 
Locality. — Near Taralga, N.S.W. 
Formation. — Pleistocene (?). 
In taking into consideration the various points considered 
above, it will be observed that the remains are those of a small 
animal in many respects resembling Gymnobelideus, but with a 
number of the characters of Petaurus. In many respects it 
stands intermediate between the two genera, and not improbably 
may be the common ancestor of both. In Gymnobelideus upper 
pm 1 and pm 3 are described as " both triangular and single 
rooted." In Petaurus all the upper premolars are "two-rooted." 
In Palceopetaurus we have the intermediate condition in pm 1 
single-rooted, and pm 3 double-rooted. Then, again, as to the 
relative sizes of these teeth, in Petaurus we have "p 1 nearly as 
large as p 4 , p 3 much smaller, but not minute." In Palceopetaurus 
pm 4 is at least a half larger than pm 1 , while pm 3 is but half the 
height of pm 1 . In Gymnobelideus the two front premolars are 
much more equal. 
In conclusion I must express my gratitude to Mr. J. J. Fletcher 
for his kindness in furnishing me with references, &c. 
EXPLANATION OF PLATE. 
Palceopetaurus elegans. 
Fig. 1. — The right maxillary teeth with palate — viewed slightly obliquely 
from below ( x 8 '3). 
Fig. 2. — Outer view of right lower jaw ( x 4). 
Fig. 3. — First and second lower molars — viewed from within ( x 16). 
