CHELONIA. 733 



females referred to B. triviUata by Theobald, because its shell much more resem- 

 bles the shells of the females than the shells of the black-striped males. Moreover, 

 although a little younger than the male (PI. Ixii), its characters are such that 

 it seems highly improbable that it could ever attain to the characters presented by 

 that species, and which is unquestionably B. triviUata, D. and E. Besides, I have 

 obtained from the Irawady young females nearly of the size as this young male, and 

 agreeing with it in every particular of shell form. These young females correspond 

 in all essential particulars to the adult females considered by Theobald to be females 

 of B. trivittata. As the young brown male cannot be reconciled as specifically 

 identical with the black-banded males ; and as moreover it does not exhibit any 

 capacity whatever, ever to change by growth into the form and colour of the 

 males of im.doubted B. trivittata, it would appear that there are two species of 

 Batagur in the Irawady closely allied by the characters of their vertebral plates 

 and skulls, but differing from each other in the general form of their shells and 

 in their coloration ; the females of B. trivittata, according to this view, being 

 unknown, whilst both sexes of the other are known, the females constituting in 

 part the species first described by Dr. Gray under the name of B.fusca, This latter 

 term, however, is open to objection, as Dr. Gray included in it two species ; there- 

 fore, I propose to distinguish the species represented by these females and young 

 male as B. iravadica. 



However, I separate these tortoises specifically with some hesitation, because the 

 skulls of the adult males and females referred by Theobald to B. trivittata are so 

 alike to one another, and so resembled by the skull even of the uniformly coloured 

 male, that I cannot seize on any cranial character which would separate them 

 specifically, unless it be the greater upturning of the nasals in the latter. Look- 

 ing, however, at the young male (PL Ixiv) as a whole, and comparing it with 

 the young male of B. trivittata, (PL Ixii), the external featm^es are very different, 

 viz., the shorter and relatively higher shell of the former, the inward projection 

 of the second costal between the second and third vertebrals, the more serrated jaws, 

 as in the female (PL Ixviii), and the uniformly brown shell compared with the 

 green thrice black-banded shell of B. trivittata. The short rounded head and the 

 spinous nodosities of the vertebrals are youthful characters. 



The shell of an adult male of B. trivittata, the sex of which was accurately 

 determined by me, presents the following characters : — 



The shell is oval, somewhat expanded posteriorly, with slightly reverted mar- 

 ginals. It is highly and roundedly arched anteriorly, and therefore deep, but the 

 posterior haK of the shell is somewhat depressed. The young male, however, figured 

 (Pis. Ixii and Ixiii) is not so liighly arched over the first and second vertebrals ; and 

 the dorsal ridge, which is absent in the adult, is strongly marked. The plastron has 

 the general form in the genus, and in the adult is devoid of the lateral ridge which 

 exists in the young. In the full-grown male, the nuchal is large, triangular, broad 

 posteriorly and narrow anteriorly, which is its general form. The first and second 

 vertebrals are of equal breadth, with their lateral margins shghtly sinuous, the shields 



