222 OPHIDIA. 



are keeled, but not prominently, arranged in nineteen lon- 

 gitudinal rows; ventral plates, 151 to 154; subcaudal, 

 fifty-three to fifty-five pairs ; anal plate double. 

 Entire length, up to 3 feet. 



This Snake so closely resembles the Common Viper as to 

 be easily mistaken for it ; it is by the wide plates and large 

 central shield of the head and forehead that it may be most 

 readily recognized. Like all others of the genus, however, 

 it is perfectly free from venomous qualities. The general 

 colour is greenish grey or duU yellow ; along the middle of 

 the back is a row of brown or black spots, either near toge- 

 ther or touching each other, sometimes so much united as 

 to form a zigzag line, as in the Yiper ; between these spots 

 are generally several black markings ; on the sides are 

 many transverse black spots, grey or greenish at their 

 centres; the belly is more or less covered with bluish 

 black spots; in most individuals there are oblique lines 

 running from the eye to the nape of the neck on each 

 side, forming by their junction there a figure like the 

 letter Y. 



MM. Dumeril and Bibron describe the " Natrix chersoides 

 et ocellata'^ of Wagler, which is probably the Coluber Vi- 

 perinus of Schinz, and Natrix Vii^erina of Buonaparte, as a 

 variety of the C. Viperinus of their great work. Its colours 

 are thus given : — 



Yar. A. Along the back are two wide, parallel, pale 

 yellow streaks, separated by a black band ; general colour 

 of the upper parts greenish brown ; beUy and flanks marked 

 most variably and irregularly bluish black. 



The Coluber Vijperinus is found very commonly in the 

 South of France in ditches and streams (Crespon), in Spain 

 and Sardinia. This Snake occurs abundantly in Italy, in 

 stagnant waters ; in France, Spain, Hungary, and Ger- 

 many. In the Canton of Ticino, in Switzerland, and in the 



