PETAURISTA. 
319 
Petaurus taguanoides and the Ph. Cookii, there certainly 
exists a great similarity in the dentition, hut the possession 
of the lateral membranes joining the anterior and posterior 
limbs, and a difference in the structure of the feet of the 
former animal, should not be entirely overlooked; and with 
regard to the group Phalangista , as constructed by F. Cuvier, 
I have to observe that he is quite incorrect in his statement 
that the teeth of the Petaurus sciureus resemble those of 
the Cuscus section, or of Phalangista vuljnna: the teeth in 
Pet. sciureus , indeed, differ more from the Phalangers with 
which they are associated, than do those of P. Cookii from 
P. vuljnna. On the whole, the more correct mode, as it 
appears to me, of expressing* the relationship of the flying 
and non-flying Phalangers, w'oukl be to arrange the species 
of these sections in two parallel series, as in my table at 
p. 12, though that table would more closely express the 
parallelism of the group, had the section Petaurus been 
placed 02 )posite Pseudochirus, and that of Belideus been 
shifted rather higher, for the animals of this latter section 
are intermediate in their characters between Petaurus and 
Acrobata , and are not represented by any known species of 
the Phalangista genus. 
Sub-genus 1. Petaurista. 
Petauri with broad, and rather short, rounded ears, which are densely 
clothed with long fur on the outer surface; the toes of the 
fore foot nearly equal in length ; the flank membrane extend¬ 
ing only to the elbow joint; with seven -well developed 
molar teeth, forming a continuous series on cither side of 
the upper jaw, and six in the lower; the true molars having 
pyramidal cusps. 
M. Desmarest divides the Petauri into two sections, making 
