149 



November 13, 183 S. 

 Professor Owen, in the Chair. 



A letter was read from G. Burghall Watts, Esq., Corr. Memb. 

 Z.S., addressed to William Yarrell, Esq., stating that a collection 

 of specimens from the neighbourhood of Turbaco, South America, 

 was on the way to England for the Society's Museum. 



A letter from Alexander Gordon, Esq. was also read, begging the 

 Society's acceptance of the animal described by Mr. Waterhouse 

 under the name of Mt/rmecobius fasciatus, and also the Perameles la- 

 gotis. Both of these animals, Mr. Gordon stated, were from Swan 

 River and not from Van Diemen's Land as had been supposed. 



A paper entitled " Observations on certain modifications observed 

 in the dentition of the Flying Opossums (the genus Petaurus of 

 authors)," was communicated by Mr. G. R. Waterhouse. 



" In the ' Dents des Mammiferes ' of M. F. Cuvier, the dentition 

 of the Flying Opossums and that of the Phalangers is described 

 under the two heads 'Petaurus' and ' Phalangers proprement dits.' 

 Both the groups termed Petaurus and Phalangers by M. F. Cuvier 

 contain certain species of Flying Opossums, and likewise species of 

 Phalangers. Those species, however, which have the flank-membrane 

 extended from limb to limb, enabling them to sail in the air like a 

 parachute, are now with universal consent separated from the Phalan- 

 gers (Phalangista), and arranged under the generic title Petaurus or 

 Petaurista. 



" In grouping the Phalangers and Petaurists as above mentioned, 

 M. F. Cuvier was guided only by the characters offered by the den- 

 tition ; that of Petaurus Taguanoides certainly bearing a very close 

 resemblance to that of Phalangista Cookii. The teeth of Petaurus 

 sciureus, however, do not bear so close a resemblance to those of 

 Phalangista vulpina and P. maculata, although the three animals 

 mentioned are placed in the same division by the author alluded to. 

 Regarding the Petauri as a distinct genus from the Phalangers, I 

 will proceed to describe their dentition as I find it in the skuUs before 

 me, which I may observe consist of two specimens of each of the 

 following species: — P. taguanoides, P. flaviventer, P. sciureus, and 

 P. pygnuEus, and one skull of a new species hereafter described. 



" In these crania three distinct modifications in the dentition are 

 observable ; and as they are combined with certain diflferences in the 

 skulls and in the external characters of the animals to which they be- 

 long, they may be regarded as forming three subordinate sections, to 

 which for convenience I shall apply the names, Petaurus, Belideus, and 

 Acrobata. Two of these names will be found in the ' Mammologie,' 

 by M. Desmarest. The dentition observable in the species of 



No. LXXI. — Proceedings of the Zoological Society. 



