REPTILES AND BATRACHIANS FROM SIAM AND INDO-CHINA. 205 



that of T. emys, but agreeing well with that of T. pseu'demys, a 

 species now recognised as T. latinuchalis* 



Testudo impressa Glinther must therefore be revived, and 

 T. latinuchalis placed under it. Apart from the skull, this species 

 can be distinguished from T. emys by the following characters : — 



T. impressa. 

 Pectoral shields always in contact. 

 Margins of the carapace usually strongly 



reverted and serrated in the adult. 

 Shell yellowish or pale brown, rich dark 



brown or black at the margins of the 



shields. \ 

 Maximum length of shell in a straight 



line 270 mm. 



T. emys. 

 Pectoral shields usually widely separated. 

 Margins of the carapace not usually strong- 

 ly reverted or serrated in the adult. 

 Shell dark horn to blackish. 



Maximum length 520 mm. 



Natrix groundwater^ sp. nov. 



Plate 8, fig. 2. 



Type d", Author's No. 3354, collected by Messrs. Robinson 

 and Kloss at Tasan, 40 kilometres S. W. of Chumpon, Peninsular 

 Siam, in March, 1919. 



Description of the type. Maxillary teeth 30,J the last not 

 abruptly enlarged ; rostral much broader than deep ; internasals 

 narrowed anteriorly, as long as the prae-frontals ; frontal once and a 

 quarter as long as broad, as long as its distance from the end of the 

 snout, much shorter than the parietals ; loreal twice as long as high ; 

 two prae- and two or three post-oculars ; temporals 1 + 2 ; 9 supra- 

 labials, 4th to 6th touching the eye ; 5 inf ralabials in contact with 

 the anterior chin-shields, which are as long as the posterior. 



Scales in 19 rows anteriorly, reducing to 17 at mid-body, and 

 so continued to the vent, smooth anteriorly, feebly keeled posteriorly. 

 Ventrals 147 ; anal 1 ; subcaudals 120. 



*. For a comparison of T. emys, T. pseudemys and T. impressa, 

 see Boulenger in Fasciculi Ma'ayenses, (1) Zool., p. 145 et seq. 



t. A specimen from Dalat, S. Annam has handsome dark brown 

 rays upon the plastron. 



+ It is unfortunate that only the type specimen is sufficiently adult 

 to allow of a satisfactory examination of the teeth, and in this specimen 

 also they are obscured by damage. It appears, however, to belong 

 to Natrix. 



VOL. IV, NO, 4, 1922. 



