1873.] DR. J. E. GRAY ON THE TRIONYCHID^. 57 



cies i of the genus or an undergrown state of the animal, the upper 

 surface of the odd bone is rather callous for a great part of its length 

 and with a few pits on its hinder margin ; therefore I strongly sus- 

 pect that, in the adult specimens, the bone is united to the ribs with 

 a callous and pitted surface, as in the Trionychina. 



Fig. 8. 



Bogania subplana. 



1. DoGANIA SUBPLANA. (Fig. 8.) 



Head pale-spotted, with a dark streak from the side of the nose to 

 the orbit. 



Trionyx subplanus, Geoff. Ann. Mus. iv. p. 11, t. 3. fio-. 2; Gray 

 Illustr. Ind. Zool. t., from Hardwicke's drawing (young)f 



Bogania subplana, Gray, Cat. Tort. B. M. p. 49, 1844 ; Ann & 

 Mag. N. H.xii. 1863, p. 158 ; Cat. Sh. Rept. p. 69, t. 33, inspirit ; 

 P. Z. S. 1862 p 265, 1864, p. 83, figs. 1, 2, 3 (skull), 1869, p. 213 

 Suppl. Cat. Sh. Rept. p. 106, fig. 35 (skull). 



Trionyx frenatus, Gray, Cat. Sh. Rept. p. 67 (part). 



Polamochelys 1 frenatus, Gray, P. Z. S. 1864, p. 87. 



Sarbieriafrenata, Gray, P. Z. S. 1869, pp. 212-220 ; Suppl. Cat. 

 Sh. Rept. p. 100. 



Bab. China and Formosa (Swinkoe) ; Singapore ?( Wallace) ; 

 not the Ganges, as erroneously stated by Dumeril and Bibron. 



Gen. Hardwicke's specimen, figured in his drawing, which is 

 copied in the 'Illustrations of Indian Zoology,' is in the Museum. 

 The front lateral bone of the sternum has indications of rugosity on 

 the inner part of the hinder edge ; but this rugosity is of an irregular 

 shape, not like the linear lateral callosities of Aspilus. All the other 

 sternal bones are smooth ; but the animal is evidently immature, just 

 noticed as a variety of Trionyx frenatus. The sternum of the' spe- 

 cimen described in Cat. Sh. Rept. as Sarbieria frenata, brought from 

 Singapore by Mr. Wallace, is about half the size of the former. The 

 front and hinder lateral bones are marked with a number of dots and 

 inosculating lines, as if they were to have, when they become older, 

 callosities covering the greater part of the central lateral portion, very 

 unlike the linear callosities of Aspihts. 



