108 BARBOUR i^ZOOGEOGRAPHY. 



Natrix trianguligera (Boie). 

 BoiB, Isis, 1827, p. 535. Boulenger, Cat. snakes Brit, mus., 1893, 1, p. 224-225. 



Type locality: — West Java {fide Schlegel). J 



Serpents of this species, together with A^. suhmmiala and A^. vittata, are the 

 common water-snakes of the rice-fields of Java. The species under consideration 

 is probably rather less common than the other two, which are both about equally 

 abundant. Before me are ten specimens from Buitenzorg, March-April, 1907, 

 and five from Buitenzorg and one from Depok in the Bryant collection. About 

 half of all the adults of these common species of Natrix have their tails bitten off, 

 evidently the work of turtles. A^. trianguligera shows in its coloration three 

 distinct growth stages. (1) In the freshly hatched young the back is olive- 

 brown, faintly barred and mottled; the throat and anterior half of the belly are 

 dull yellow, with a coppery tinge; this color extends up between the lateral 

 triangular markings of the olive; the tail is encircled by many complete black- 

 brown rings; the ground color of the ventral surface of the tail and the posterior 

 half of the belly is ivory-white. (2) In half-grown examples we find a red 

 blotch situated between the dark lateral markings on the anterior part of the 

 body, while on the posterior part the markings become indistinct. (3) In fully 

 adult specimens the whole dorsal and lateral surfaces become mottled olive, 

 the lateral triangular spots show as faint darker areas. The whole lower surface 

 of body and tail becomes white. The rings under the tail show only as the 

 faintest dark lines. 



All of the specimens show great uniformity in the number of ventral scales. 

 The range is 137-143, and the average 140; on the other hand the number of 

 subcaudals may vary greatly; the range 67-99 exceeds by five that given by 

 Boulenger for specimens from widely separated localities. The single specimen 

 from Java in the British museum had scales 139-69. Speaking generally from 

 Boulenger's figures, the Bornean specimens seem to average lower and Sumatran 

 higher in scale numbers than the Javan. But nothing conclusive can be said 

 without far larger numbers. 



This snake has a wide range, from Burma and Malaya to Sumatra, Nias, 

 Java, and Borneo. 



Natrix sancti-johannis (Boulenger). 



Boulenger, Fauna Brit. India. Rept. Batr., 1890, p. 350; Cat. snakes Brit, mus., 1893, 1, p. 230, pi. 15, 

 fig.l. 



A single very large specimen of this species from a pond near Lucknow, 



United Provinces, India, November, 1907. This form, judging from this and 



