SNAKES OF CEYLON. 547 



Genus ANCISTRODON. 



(Greek " agkistron " a hook, and " odous " tooth.) 



General Characters. — The species are small, varying from 

 about 18 inches to 3 feet in their adult state. The head is 

 flat, suhtriangular in shape, and broadest about midway 

 between the eye and the neck. The snout is moderate in 

 length, attenuated towards the tip, has a pronounced canthus, 

 and may or may not have an eminence or scaled appendage 

 on the anterior part above. A loreal pit is present between 

 the eye and the nostril. The eye is moderate, being about 

 half the length of the snout ; the iris speckled with ruddy 

 gold, and the pupil vertical. The nostril is pierced near the 

 middle of the nasal shield. The neck is much constricted. 

 The body is moderate in length, cylindrical, and robust. The 

 belly is rounded. The tail is short, being about one -sixth to 

 one -eighth the total length. 



Identification. — The combination of loreal pit and enlarged 

 shields on the head will establish the identity of the genus 

 in Ceylon. 



Habits.— Terrestrial, partially, if not wholly, nocturnal ; 

 sluggish; viviparous, except A. rJiodostoma; poisonous, but 

 rarely fatal to man. 



Food. — Mammals, lizards, batrachians, reptilian eggs, and 

 sometimes scolopendrse. 



Lepidosis. — Rostral : Touches six to nine shields ; the rostro- 

 nasal sutures twice the rostro -labial. Internasals : Two 

 more or less in contact. Prefrontals : Two, sometimes 

 touching the internasals in front and the frontal behind, some- 

 times not. Frontal : Touches six to eight shields ; the 

 fr onto -supraocular sutures greater than the fr onto -partietaJs. 

 Supraoculars : As long or longer than the frontal, as broad or 



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