258 OPHIDIA. 



head. The vertical is pentagonal, much broader than the superciliary, and not quite twice 

 as long as broad ; its lateral margins are nearly parallel ; the posterior ones very short, and 

 meeting at a right angle. The occipitals are slightly elongate and rather narrow, subtrun- 

 cated posteriorly. Nostril between two plates; one loreal, one anterior, and two posterior 

 oculars ; eight upper labials, the thu-d, fourth, and fifth of which enter the orbit. There 

 appear to be five temporal shields. Ten lower labials, those of the first pair being in contact 

 with each other, behind the median shield, which has the posterior margin obtusely rounded. 

 Two pairs of chin-shields, the anterior being the smaller. The trunk is compressed, especially 

 towards the tail, and slender ; it is surrounded by nineteen series of scales, those of the back 

 being slightly keeled ; they are rather elongate, and assume a rhombic form towards the tail. 

 The ventral and subcaudal plates are bent upwards to the sides, but not keeled. Ventrals 

 216; anal bifid; caudals 90. 



The two posterior teeth are twice as long as the anterior, with which they form a con- 

 tinuous series ; they are not grooved. The upper parts are uniform greenish brown, the 

 lower parts yellowish ; the ventrals have an elongate spot on each side. 



The single specimen I have seen has the head injured ; it was procured by Messrs. von 

 Schlagintweit in Sikkim, at 7500 feet above the level of the sea. Total length 3 feet 1 inch ; 

 length of the head 10 lines, of the tail 9 inches. 



Coluber jprasinus (Blyth, Journ. As. Soc. Beng. xxiii. p. 291), from Assam and Tenasserim, 

 is perhaps the same snake ; but it would be hazardous to name a species from so insufficient 

 a diagnosis as that quoted. 



TROPIDONOTUS, Kuhl. 



Body cylindrical ; head distinct from neck, flat, cleft of the mouth wide ; 

 eye of moderate size, or rather large, with round pupil ; nostril lateral, 

 between two plates. Shields of the head regular ; loreal always present. 

 Scales keeled ; ventrals rounded, considerably less than 200 in number ; 

 anal bifid ; subcaudals two-rowed. Teeth numerous in the jaws and on 

 the palate : the anterior in the jaws are always shortest ; the posterior 

 lengthened, but not grooved. 



The typical Tropidonoti are easily recognized by their stoutish, cylindrical body, keeled 

 scales, flat head covered with very regular shields, wide cleft of the mouth, and numerous 

 teeth, the strongest of which are at the hinder end of the maxillary bone. They frequent 

 the neighbourhood of fresh waters, and feed on aquatic animals — frogs, toads, and fishes. 

 They do not overpower or kill their prey by throwing a coil of the body round it, but. 



