208 dr. malcolm smith on 



Peninsular Siam. 



1 praeocular; ventrals 150-157; subcaudals 72-82. 

 Colour as above. (5 specimens). 



S. E. Siam. 



2 praeoculars; ventrals 156-164; subcaudals 74-84. 



Adult with cross bands hardly distinct or absent. Posterior 

 1/3 of belly and tail sparingly powdered grey. (4 specimens). 



Other variations. The postoculars may be 3 or 4 in number; 

 the temporals are usually 2 + 2, but in one example (No. 3090) are 

 1 + 2 ; 9 supralabials is the rule, but in two examples there are 8 

 on one side ; the outer row of scales is variable as regards the strength 

 of the keeling, which may be entirely absent. 



I have no hesitation in placing under this species Gylden- 

 stolpe's Tropidonotus eisenhoferi from N. Siam. Its separation 

 from Natrix nigrocinctus upon 4 postocular shields and an outer- 

 most row of smooth . body scales, is untenable with the series 

 now shewn. 



Holarchus longicauda (Boulenger). 



Simotes longicauda, Bouleng,, Ann. & Mag. Nat. Hist., 1903, (7) 



xii, p. 350. 

 Simotes longicauda joynsoni, Smith, Journ. Nat. Hist. Soc. Siam, 



1917, ii, p. 276. 



Last year when home on leave I was able to compare my 

 S. I. joynsoni with Boulenger's type of longicauda in the British 

 Museum. The difference in colouration between them was far less 

 than I had gathered from the description, so much so that mine can 

 no longer be recognised as a form apart. 



Since Mr. Joynson obtained his specimens, I have examined 

 four more from Siam, two from the Me Wang forest and two from 

 Pak Jong in the Dong Rek mountains. They show well the great 

 variability of the species with regard to colouration and markings. 



Lygosoma vittigerum kronfanum,* subsp. nov. 



Type, Author's No. 2417, collected at Daban, Langbian 

 plateau, S. Annam, in March 1918. 



* Named after the Kronfa river on the banks of which the specimens 

 were obtained. 



JOURN. NAT. HIST. SOC. SIAM. 



