REPTILES AND BATRACHIANS FROM SIAM AND INDOCHINA- 207 



Each region appears to have its own variation, which, with the 

 material now available, may be chronicled as follows : — 



NORTHERN SlAM. 



1 praeocular; ventrals 161-168; subcaudals 85-96. 



Adult with distinct black cross bands ; posterior 2/3 of belly 

 and tail thickly powdered with grey, or tail below entirely dark 

 grey. (10 specimens). 



Details of specimens of N. nigrocinctus. 



* Indian Museum number, 

 pared with my series. 



One of the types which I have com- 



VOL. IV, NO. 4, 1922. 



