Zoological Society. 49 



behind : a small anterior tubercle is separated from the body of the 

 tooth by a sli ht transverse incision. The true molars resemble 

 those of the upper jaw, excepting that they are narrower, and the 

 last molar has four tubercles instead of three. 



" The above description is taken from P. Taguanoides . The cra- 

 nium differs from that of the species of the second section (Belideus), 

 in being proportionately smaller, more contracted, and deeply con- 

 cave between the orbits ; the cranial cavity is smaller, the zygoma- 

 tic arches deeper, and the bony palate is deeply emarginated poste- 

 riorly ; in fact, the palatine portion of the palatine bone is wanting. 

 The dense woolly fur on the outer side of the ears will serve to dis- 

 tinguish the animal externally from either of the species of the next 

 subgenus. P. macrourus I suspect belongs also to this section. In 

 M. F. Cuvier's ' Dents des Mammiferes,' it is stated, that besides the 

 false molars described by me there are two others on each side, 

 which are small ; — these I have not seen, nor are they shown in the 

 plate of the work quoted. Perhaps they are shed at an early pe- 

 riod, or perhaps M. Cuvier may have described the dentition of 

 Phalangista Cookii and figured that of Petaurus Taguanoides. 



" Section 2. Belideus. — Dentition: Incisors, ^; canines, ^ ; false 



molars, ^; true molars, ^=40. The anterior incisors of the 



upper jaw are large, somewhat suddenly dilated immediately above 

 their insertion in the intermaxillaries, and assuming a triangular 

 form. In P.flaviventer they are broader than in either P. sciureus or 

 the new species here described under the specific name of breviceps, 

 where these incisors are proportionately shorter, and perhaps a little 

 broader than in P. sciureus. The next incisor on each side is smaller 

 than the posterior one, narrow at the base, and broad at the apex. 

 The third incisor is broad, and has a sharp incurved cutting edge. 

 The canine is tolerably large, and has its origin close behind the in- 

 termaxillary suture ; in fact, is in the usual situation of the canine. 

 It is separated by a small space on either side from the false molars 

 and the incisors, compressed and pointed, and its anterior and posterior 

 edges are sharp. The apex projects beyond the level of either of 

 the molars. The first false molar on each side is rather large, broad, 

 compressed and pointed, has a very faint indication of an anterior 

 and posterior lobe, and two distinct fangs (which is not the case in 

 the small and cylindrical corresponding tooth in Petaurus Tagua- 

 noides). The second false molar is small, short, and compressed, 

 and has a minute anterior lobe. This tooth is separated by a con- 

 siderable space from the first false molar, and by a narrow space from 

 the third. The latter touches the first true molar, is narrow in 



