48 
ROOM X. 
Nat. Hist. 
The Vipers ( Vipera ) have the same broad head as 
the Rattle Snakes, but they have no pit before the eyes. 
Amongst these the True Vipers ( Vipera) are distin¬ 
guished by the head being covered with scales like 
those on the back, and by the nostrils being very large. 
Amongst these there are the Nose-horn Viper (Co/. 
nasicornis), peculiar for two horns on the end of the 
nose; the Cerastes (Col. cerastes ), the male of which 
has a long horn-like scale over each eye, which being 
wanting in the female, has caused the latter to be erro¬ 
neously described as a distinct species ; the Puff Adder, 
or Short Tailed Viper ( Vipera inflata), the most deadly 
snake of the Cape; and Russel’s Viper (Col. Russell). 
The Adders (Berus) have the head covered with 
granular scales and the nostrils moderate; as the Black 
Adder (Col. berus), and the Ammodyte Adder (Col. am - 
modytes) from the shores of the Mediterranean, very 
peculiar for the end of the nose being lengthened into 
a flexible horn. 
The Common Adder (Col. cherlca) differs from these, 
by the crown of the head having three larger scales in¬ 
serted amongst the smaller ones ; this is the only rep¬ 
tile found in Great Britain possessed of dangerously 
poisonous qualities. 
The Elaps or Cylindrical Snakes differ from the other 
venomous reptiles, by the head being much smaller, 
scarcely so broad as the body, and by its being covered 
with large regular plates, and without any pit on the 
cheek. 
Some of these, as the Spectacle Snake or Naja, have 
the faculty of dilating the skin of the neck, by the ex¬ 
tension of their ribs, so as to form a kind of hood over 
the head; they are also peculiar from the body being 
covered with very narrow scales. 
The Indian species have usually a yellow spot on the 
back of the neck, somewhat resembling a pair of spec¬ 
tacles. These snakes are used by the Indian jugglers, 
in their exhibitions. 
The Coral Snakes (Elaps) are very similar in form, 
but 
