382 Note hy Dr. J. Anderson on 



narrow black median band is generally limited to the nuchal 

 region, rarely extending to the end of the trunk. 



Cape Colony. Several specimens from Sir A. Smith's col- 

 lection. The body of the largest is 63 millims. long. 



XL. — Note on Trionyx gangeticus, Cuvier, and Trionyx 

 hurum, B. Hamilton. By John Anderson, M.D., Calcutta. 



Having examined forty-five living specimens of a Trionyx 

 the young and adolescent individuals of which agree in their 

 form and coloration with the figure given in Hardwicke and 

 Gray's '■ Illustrations of Indian Zoology ' as Trionyx java- 

 nicus^ Schw., and having removed the skulls and compared 

 them with Cuvier's figure of T. gangeticus^ I do not hesitate 

 to refer them to one and the same species, i. e. T. gangeticus^ 

 Cuvier ; the adult skulls in form and size agree with the 

 skull figured by Dr. Gray as T. gangeticus^ Cuvier ; whereas, 

 on the other hand, the Trionyx hurum and T. oceUatus of 

 Dr. Gray (that is, specimens corresponding exactly with these 

 drawings, which Dr. Gray afterwards referred to the T. gan- 

 geticus of Cuvier) yield skulls quite distinct from Cuvier's 

 figure of the skull which he regarded as the Trionyx du Gangel 

 The true Trionyx gangeticus, Cuv., is therefore the species 

 which has hitherto gone under the name of TjavanicuSySchw., 

 if by the latter were meant Trionyches agreeing with the figure 

 so named in the ' Illustrations of Indian Zoology.' The skulls, 

 however, of such forms, as they answer in every detail to 

 Cuvier's figure, could not well be referred to any other species; 

 so we have here another instance of a Chelonian animal as a 

 whole having a specific geographical name allocated to it, 

 while its dismembered skull has awarded to it another but 

 kindred term. The cause of this unfortunate jumble of names 

 as applied to the Trionyx of the Ganges, and each of which 

 implies a distinct theory as to its distribution, is not difficult 

 to explain, so long as animals are described, as in this case, 

 from drawings, without any practical knowledge of the struc- 

 tural characters of the animal itself. 



One hundred and twenty examples, living specimens, shells, 

 and sterna, of the common Trionyx of the Ganges have passed 

 through my hands ; but in collecting them I succeeded in ob- 

 taining only two individuals agreeing with Dr. Gray's figures 

 of T. Jiuricm and T. oceUatus. The abundance, therefore, of 

 the former indicates the propriety that, in one sense, exists in 

 the name given to it by Cuvier. Specimens agreeing with 

 the last-mentioned figures yield skulls in no way resembhng 

 the skull figured by Cuvier as T. gangeticus. The head- 



