Histoire Naturelle des Mammiferes. 423 



trifling, and the part which unites the second to the third being 

 more prolonged internally ; modifications which though apparently 

 flight, are sufficient to distinguish without any difficulty these 

 teeth from all others. 



At the period of proposing this genus, and even at that of 

 describing the S. guitatus, M. F. Cuvier was acquainted with only 

 this species. He suspected indeed that several American animals 

 hitherto described as Marmots, would eventually prove to be 

 Spermophilt, but it was not until after publishing the Souslik that 

 he was enabled, from actual observation, to establish this fact 

 with respect to one species at least, the Sciurus tredecim-lineatus 

 of Dr. Mitchell and Arctomys Hoodii oi Mr. Sabine. The loca- 

 tion of this species in the genera Sciurus and Arctomys respec- 

 tively aflfords a strong prima facie presumption of its osculant posi- 

 tion between them, which is confirmed by its habits, and finally 

 proved by actual examination. 



Such are the principal features of the present numbers of this 

 valuable publication ; but there are yet a few others to which we 

 shall cursorily advert. For the Coendou, Hystrix prehensilis L. 

 M. F. Cuvier proposes to employ the generic name of Sinetherus 

 instead of the common appellation which was used for that pur- 

 pose by Lacepede upwards of twenty years since; an alteration 

 which appears to be quite unnecessary. Another alteration is 

 proposed in the name Aotus^ used to designate a genus of Ameri- 

 can Monkeys, by Humboldt. This name being inapplicable to 

 all the species, some of which possess very visible ears, M. F, 

 Cuvier would prefer that of Nocthora. The same fact had how- 

 ever been previously observed by M. Spix, and the appellation of 

 NyciipiihecuSy given by him, has the advantage of priority. The 

 Aperea, the animal that consituteb the stock from whence the 

 Guinea Pigs are derived, is distinguished by the new generic 

 name of Kerodonta. 



M. F. Cuvier regards the dismemberment of the genus Phalan- 

 gista, adopted by M. Temminck, in his Monographies de Mam- 

 malogie, as founded on erroneous principles. The modification 

 of the organs of motion by the presence or absence of a flying 

 membrane, is merely a secondary character, and consequently 



