230 SPOLIA ZBYLANICA. 



are omitted. The earth-snakes ('*depat-naya"), the Python or 

 rock-snake (" pimbura "), and the Vipers (" polonga ") are not 

 included within the scope of the schedule. 



Two points may be noted in connection with the guiding 

 characters which I have selected in the index. All the species 

 mentioned have less than thirty rows of scales round the body 

 (excluding the ventral shields) and in all cases the general con- 

 dition of the head-shields is normal and remarkably constant on 

 the whole. Seen from above there is a rostral shield in front 

 (usually barely visible in dorsal view) followed by a pair of 

 internasal shields between the nostrils, then a pair of praefrontals, 

 a median frontal between two supraoculars and a pair of parietals 

 behind. The shields which appear in side view of the head are 

 less constant, the most important feature being the presence or 

 absence of a loreal shield between the praeocular and the nasal, 

 this being one great distinction between Lycodon and Bun- 

 f/arus. 



When once a character has been observed all the species which 

 are shown by the index not to possess this character are excluded, 

 and thus by continuing the process of exclusion at least the genus 

 of the specimen can be fixed with certainty, and this is enough for 

 practical purposes. 



1-7 



^ 



A. Side view of head of Ljjcodon nulicus ; I. LorcaJ «liield; L". Ninlli 

 upper labial. 



B. Side view of head of Bungarus ccylonicus ; showing absence of loreal 

 shield; L\ Seventh upper labial. 



The species which oflEers the most generalized characters is No. 

 XII., Pulyodontophis subpanctatus, a harmless snake which may 



