CHELONIA. 779 



This species occurs in the Sunderbunds to the east of Calcutta, and is more 

 common than B. lineata. How far it extends to the westward I cannot say, but 

 it appears probable that its place is taken in the north-west by B. lineata and 

 B. duvaucellij and that it is more essentially a Malayan than an Indian form. 

 I have received it from the coast of Arracan, and it is generally distributed 

 throughout the Irawady. 



I have carefully examined the type of T. longicolUs, and do not find any charac- 

 ter by which it can be separated from B. basJca. 



TRIONYCID^. 



Genus Em yd A, Gray. 



Emyda scutata, Peters. Plates LXXIY, LXXY, & Plate LXXV^- 



Emyda granosa, Theobald {pars), Journ. Linn. Soc, vol. x, p. 18, 1868. 



Emyda scutata, Peters, Monatsbr. Preuss. Akad., 1868, p. 449 ; Gray, Suppl. Cat. Sbd. Rept., B. M., 

 p. 107, 1870; Theobald, Descr. Cat. Eept. Brit. Ind., 1870, p. 32. 



This is a shorter and more rounded oval than any of the other species of the 

 genus, and if the nuchal valve is excluded, the anterior and posterior margins of 

 the shell are rounded nearly to the same extent. The nuchal is very small and 

 suspended in a cartilaginous flap. The anterior vertebral swelling is better defined 

 in the male than in the female. The first costal area in the female is markedly 

 concave. The marginals in the adult are nearly all of one size, whereas, in the other 

 forms, the first marginal is always much larger than the rest. The plastron is 

 known by its very much smaller epiplastra, hyoplastra, and hypoplastra, and by 

 its very large entoplastron, characters which separate it from all the other species ; 

 also, by its closely approximated xiphiplastra, broad anteriorly and narrow posteriorly, 

 their inner margins forming a straight line, with no divergence either anteriorly or 

 posteriorly. 



The sexes are distinguished by well marked characters. The males are smaller 

 than the females, and the callosities of the plastron in the male are relatively larger 

 than in the female. In a fully grown male measuring 7"*50, the epiplastra are 

 triangular with a long anterior border. The inner margin is slightly convex, 

 but nearly straight, while the posterior margin is nearly transverse, being directed 

 slightly backwards, these two margins each equalKng two-thirds of the length of 

 the anterior margin. The callosities are rather widely separated by an interval, 

 equalling nearly one-half of the length of the internal margin, but being broader 

 anteriorly and posteriorly, owing to the convexity of the inner margins. Each 

 epiplastron is much smaller than the entoplastron, the extreme length of one of 

 these being less than the transverse breadth of the entoplastron, but exceeding its 

 longitudinal breadth, the greatest breadth of an epiplastral callosity being little 

 more than three-fourths of the latter measurement of the entoplastron. The 

 entoplastron is transversely oval, the posterior side being somewhat swollen; its 



