8. PBTATJEOIDES, 163 



8. PETAUEOIDES *. ^^^ 



Voluccella, Sechst. Uebers. vierf. Thiere, ii. p. 351. (1800) 



[nee Fabricius (Diptera), 1794] P. volans. 



Petaurista, Desm. Mamm. i. p. 268 (1820) \nec O. Fisch. 



Zoogn. iii. p. 498 (1814) (=Pteromys)] P. volana. 



Size large. Fur exceedingly long, soft, and silky. Ears very 

 large, oval, their backs entirely and closely covered with fur similar 

 to that on the crown, their insides quite naked. Flanks with a 

 flying-membrane, stretching from the wrist to the ankle, but very 

 narrow along the sides oi the forearm and lower leg (see PI. XVII. 

 fig. 2). Fore toes subequal, their respective lengths in the following ' 

 order — 4, 3, 5, 2, 1. Claws very long, strongly curved, sharply 

 pointed. Tail long, cylindrical, evenly bushy, except just below its 

 extreme tip (PI. XVII. fig. 3), where it is naked and prehensile. 

 No crown- or chest-glands present. 



Shull (PI. XVIII. fig. 1) short and broad. Nasals short, the 

 premaxillse projecting some way in front of them. Interorbital 

 space narrow, much contracted, its edges strongly marked, slightly 

 inflated anteriorly, sharply beaded posteriorly. Squamosal portion 

 oi zygomata slightly inflated. Palatal foramina reaching to the 

 level of p".' Posterior palate with two large vacuities opposite the 

 molars. Bullae inflated, smoothly bulbous. Lower jaw with a 

 distinct opening leading from the masseteric fossa into the inferior 

 dental canal. 



Bmtition :-I. J-44, C. \, P. ^i?^^^^f|-|, M. ;-44^=17-Kat 

 most) 3 (or lQ+4) x 2=40. 



All the upper teeth (PI. XVIII. fig. 2) very uniform in height. 

 I.' not much exceeding the others in length. Canine smaller than 

 i.' and situated some way behind it. P.^ still smaller than canine, 

 similar in shape, sometimes minute or absent ; diastemata in front 

 of and behind it about equal. P.' and p." both large and functional, 

 about equal in height to the molars, and quite in even series with 

 them J p.^ about two thirds the size of p.* in section. Molars large, 

 oblong, the usual rounded cusps found in the previous genera 

 modified into sharp points, with curved ridges radiating from them. 

 Lower minute intermediate teeth often entirely absent, and very 

 seldom more than two or three in any one jaw ; if these are present 

 they would appear to be i.^, p.', and p.^ P.* large and functional, 

 as high as the molars. Molars with sharp curved crests- much as 

 in the upper jaw. 



Range. That of the only species. 



This genus occupies the same relation to Pseudochirus that 

 Petaurus does to Gymnobelideus, its identity in cranial and dental 

 characters being even more complete (especially as compared to 

 P. lemuroides). On the othei; hand, it is externally exceedingly 

 different, not presenting even the superficial resemblance to the 

 non-flying forms that is found in the parallel case. 



* Nom. nov. 



m2 



