A POPULAR TREATISE ON THE COMMON INDIAN SNAKES. 73 



removed it from this genus on account of its corporeal habit which is 

 much shorter, and stouter than that characteristic of Psammophis, and 

 introduced the present generic name. There is no doubt that the two 

 genera are very distinct, for though the maxillary dentition is very 

 similar in both, I notice that there is a short edentulous gap between 

 the 4th tooth, and the succeeding enlarged pair in Psammophis which 

 does not occur in Psammodynastes. Of much greater significance how- 

 ever are the differences in shape of the preemaxillary, nasal, and frontal 

 bones especially the last. Further the palatine bone in Psammophis 

 is unusually short, not extending as far as the 4th maxillary tooth 

 whereas in Psammodynastes it extends forwards to the 2nd tooth. 



The genus Psammodynastes has but two species, one peculiar to the 

 Malayan sub-region, vie, pictus, the other also a Malayan snake whose 

 range of distribution extends through a considerable area of our 

 Indian Dominions, viz., pulverulentus. 



Nomenclature — (a) Scientific. — The generic name is from the Greek 

 " psammos " sand, and " dunastes" a ruler. The specific title is from 

 the Latin, meaning dusty. 



(b) English. — The mock viper seems to me the most appropriate 

 name for it, for it bears a very marked superficial resemblance to a 

 viper, a fact remarked upon by most previous writers. Its similarity to 

 the Himala}*an pit viper Ancistrodon himalayanus is especially striking, 

 as will be seen from our Plate, and I know of no more remarkable 

 resemblance between any two snakes of different families, or even 

 genera. The short and rather stout body, contracted tail, flattened head, 

 swollen lips, large eye with vertical pupil, lustreless dorsal scales, and 

 highly polished ventral plates are all very characteristic viperine traits, 

 but the resemblances do not stop here, for its attitude of menace is 

 very like that of vipers, added to which it is viviparous in habit. 



(c) Vernacular. — I know of none. 



General characters. — The head is flattened on the top, and rather 

 almond-shaped, the snout narrowed in front, and rather short, and the 

 neck very obviously constricted. The ridge from the eye to the snout 

 (canthus rostralis) is very marked, separating the face from the crown. 

 The upper lip is rather swollen giving a forbidding expression to 

 the facies. The nostril is placed in a single shield, and the eye 

 which is large has a vertically elliptic pupil, and an iris specked with 

 gold. The body is rather stout, and short, and markedly compressed. 



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