SNAKES OF CEYLON. 559 



vertical. Nostril small, round, and pierced about the middle 

 of the nasal shield. Neck very much constricted. Body 

 moderately elongate, cylindrical or compressed, robust, 

 attenuating considerably to the neck and more gradually 

 towards the vent. Belly rounded. Tail prehensile in the 

 arboreal species, short, or moderate ; varying from one-fifth 

 to one-eleVenth the total length. 



Identification. — Known by the loreal pit and the whole 

 crown of the head being covered with small scales. (Except 

 macrolepis, which has large shields on the crown.) 



Habits. — ^Terrestrial, arboreal. Usually sluggish, but fierce 

 when roused. 



Food. — Chiefly mammals, but also birds, lizards, and 

 batrachians. 



Breeding. — Viviparous, except the famous American bush- 

 master {T. mutus) and the Himalayan (T. monticola) . 



Poison. — ^Poisonous, but mostly not fatal to man. 



Lepidosis. — Rostral : Usually in contact with more than six 

 shields. Internasals : Usually present ; when present, in 

 contact or separated. Supraoculars : Usually Well developed 

 and entire, sometimes divided. Nasal : Entire or subdivided ; 

 sometimes confluent with 1st supralabial ; in contact with the 

 2nd supralabial, or separated by small intercalary scales. 

 Preeoculars : Three ; the median and inferior divergent to 

 border the loreal pit. Postoculars : One or two. Suboculars : 

 One, two, or many. Supralabials : Seven to fourteen ; upper- 

 part of the 2nd usually forming the floor of the loreal pit ; 

 none touching the eye. Sublinguals : One pair ; in contact 

 \vith three or four infralabials. 



Costals : Longer than broad ; rectiform ; smooth or keeled ; 

 in 13 to 27 rows. The vertebrals not enlarged. Ultimate 

 row, with one exception (viz., macrolepis), enlarged. Ventrals : 

 Rounded. Anal: Entire. Subcaudals : Divided. 



Dentition. — Maxillary : A pair of large canaliculate fangs 

 placed side by side. Palatine : Edentulous in jerdoni, and the 

 posterior third or half edentulous in most of the other Asiatic 

 species ; teeth large, isodont, and number from 2 to 6. 



