512 Mr. Bell on a new Genus of Freshwater Tortoises. 



longicollis might prove to be the type of a genus, and subse- 

 quent observations upon several other species have convinced 

 me that the conjecture was correct. The characters which 

 appear to me to call for this distinction, are the following. The 

 head and body are much depressed ; the nose projecting, narrow, 

 and the nostrils near together ; the neck is very long and ex- 

 tensile ; the feet flat, and very perfectly palmated. The first 

 vertebral scutum is exceedingly broad anteriourly, constituting 

 a very remarkable peculiarity, and there are invariably thirteen 

 sternal plates, a number which does not exist in any other 

 species of the digitated families, excepting Sternolhcerus Leach- 

 ianus^ and the two species of Chelys. It is on the union of all 

 these characters in a greater or less degree in the whole of the 

 group, that I have thought it necessary to found the proposed 

 genus, which I shall designate by the name of Hyduaspis. 



It is evident that in some of the circumstances now enume- 

 rated, there is a marked approach to the family Trionychida, 

 particularly in the great length and extensibility of the neck, 

 the general flatness of the body, the prominence of the nose, 

 and the breadth of the web connecting the toes. In other 

 minor respects, however, as the broad and entire sternum for 

 instance, the two groups are as far removed as possible from each 

 other. 



I am not acquainted with any undescribed species, but the fol- 

 lowing are those of former authours of which this genus is at pre- 

 sent constituted : viz. Testudo longicollis^ which I consider the 

 type ; T. galeata of Schoepff, (the synonymes of which include T. 

 scabra of Retz, T. subrufa of authours, T. olivacea of Schweiger, 

 and some others) ; T. planicepSy Schoepff", (the same with 

 Emys canaliculata of Spix) ; and probably the whole of the fol- 

 lowing from the magnificent work of Spix on the Repiilia of 

 Brazil ; Emys Amazonicay E. viridisy E. depressa, E. macro- 

 cephala^ E. Tracaxa, E. rufipes. Of these some appear to be 

 more nearly allied to the typical form than others, and it is 

 possible that a better acquaintance with them may lead to a 

 d liferent arrangement from that now suggested ; I have at all 

 events thought it necessary to hesitate before I decided on the 



