570 FOSSIL MARSUPIAL ALLIED TO PETAUBUS. 



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 m^ 3*3 



Depth behind m^ 3 8 



Lower molars 6 '3 



Incisor 5* 



Incisor to m* 13* 



Upper jaw. 

 Canine, height about I'lmm. 



ant. post, length about... 11 ,, 



1st premolar, height '8 ,, 



ant. post, length '9 ,, 



3rd premolar, height '4 ,, 



ant. post, length T ,, 



4th premolar, height 1 '2 ,, 



ant. post, length 1*6 ,, 



1st molar, ant. post, length 1-8 ,, 



2nd molar, ditto TT ,, 



Locality. — Near Taralga, N.S.W. 



Formation. — Pleistocene (V). 



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 GymnoheJideus, but with a 

 number of the characters of Petaiirus. In many respects it 

 stands intermediate between the two genera, and not improbably 

 may be the common ancestor of both. In Gymnobelideus upper 

 pm^ and pm'^ are described as " both triangular and single 

 rooted." In Petatirus all the upper premolars are "two-rooted." 

 In PalcEopetaurus we have the intermediate condition in pm^ 

 single-rooted, and pm^ double-rooted. Then, again, as to the 

 relative sizes of these teeth, in Petaurus we have "p^ nearly as 

 large as p'^, p'^ much smaller, but not minute." In Faloiopetaurus 

 ^m.^ is at least a half larger than pm^, while pm'^ is but half the 

 height of pm^. In Gyinnohelideus 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 elegavs. 



Fig. 1. — The right maxillary teeth with palate — viewed shghtly 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). 



