Zoological Society \ 51 



" In the third section, which is the subgenus Acrobata of Des- 

 marest, the incisors are | ; canines, ^ ; false molars, ^ ; true mo- 

 lars, J-i=36. The incisors resemble those of Belideus; the canines 



are well-developed, long, pointed, and recurved, placed close to the 

 intermaxillary suture, and even encroaching slightly on the intermax- 

 illary bone. The three false molars of the upper jaw have each two 

 fangs, they are compressed, sharply pointed, and viewed laterally, of 

 a triangular form. The first and second are about equal in size, and 

 larger than the third, the apex of which projects beyond the level 

 of the crowns of the true molars. Between the first and second false 

 molars on each side there is a narrow space ; the third is placed 

 close to the true molars ; these as well as those of the under jaw 

 resemble the true molars of Belideus ; there is however one less on 

 each side of both jaws. The incisors of the lower jaw also resemble 

 those in Belideus. Behind these incisors there are two minute teeth 

 on each side, which are followed by two sharply pointed false molars, 

 the foremost of which is the larger, and the apex of the second is 

 raised above the plane of the true molars. 



" The difference in the form of the false molar teeth pointed out, 

 together with the reduced number of true molars, the slenderness 



the zygomatic arch, and the incurved angle of the lower jaw, 

 combined with the imperfect state of the palate, will serve to distin- 

 guish the species of the present section from the preceding. Exter- 

 nally, the P. pygmcevs (which is the type of M. Desmarest's sub- 

 genus) may be distinguished by its distichous tail. 



Petaurus breviceps. P. cinerea, lined dorsali longitudinali 

 membrandque laterali supra nigrescentibus, hac ad latera alba / 

 corpore subtiis sordide et pallide cinereo : caudd gracili, ad 

 apicem fuliginosd ; auribus mediocribus, 



unc. lin. 

 Longitudo ab apice rostri ad caudae basin .... 6 6 



caudce 7 



tarsi digitorumque 1 1 



— auris 9 



Habitat New South Wales. 



" This species very much resembles the P. sciureus in colouring ; 

 the under parts, however, have a distinct grayish tint : the dark 

 mark which extends from the tip of the nose along the back is in- 

 distinct. It is of a much smaller size than P. sciureus, the tail is 

 much more slender, and occasionally has a white tip. The skull is 

 proportionately broader and shorter than that of P. sciureus, as will be 

 seen in the following dimensions." 



