SNAKES OF CEYLON. 101 



Gostals : Longer than broad ; rectiform ; keeled, except 

 the last one, to three rows ; emarginate. Vertebrals about 

 half their length, and half those of the ultimate row. 

 The last two rows are enlarged. Ultimate row broadest ; 

 the breadth of its scales about equal to their length. In 

 19 rows two heads-lengths behind the head, 19 rows at mid- 

 body, and 17 two heads-lengths before the vent. The 

 reduction in rows takes place behind midbody, and is due 

 to the absorption of the fourth row from the ventrals. 

 Ventrals : Rounded ; 125 to 152. Anal : Divided. 

 Supracaudals : In even rows, keeled till after the fours are 

 established. Subcaudals : Divided ; 64 to 95. 



(b) Anomalies — Inter nasals : I have rarely seen one, and 

 as rarely three . Prefrontals : I have seen four in a single trans- 

 verse series, and Mr. Green has told me of a specimen with 

 only one. Nasals : I have seen these very rarely meeting 

 behind the rostral. Postoculars: Not unusually there are 

 two, or four, or even five. Supralabials : Frequently some 

 of the series are confluent. Sometimes only the 4th or only 

 the 5th touches the eye. I have seen ten rarely. Temporals : 

 Rarely but one. Anal : Very rarely is entire. Subcaudals : 

 Occasionally a few may be entire. 



Dentition. — From eight skulls in my collection. Maxil- 

 lary : 21 to 26. Palatine: 11 to 16. Pterygoid: 22 to 33. 

 Mandibular : 22 to 27. In my Ceylon skull the maxillary 

 are 21 to 22, the palatine 11 to 12, the pterygoid 22 to 24, 

 and the mandibular 22. (Fig. 23.) 



Fig. 23. — Mexilla of Nerodia piscator. 



Distribution. — (a) General : Peninsular India to Sind and 

 Baluchistan in the north-west, and Assam in the north-east. 

 Burma, Indo -China, to Southern China and Formosa. The 

 Malay Peninsula and Archipelago as far east as Java. 

 Ceylon and the Andamans Islands. 



