ROOM X.] 
NATURAL HISTORY. 
39 
the Purple-spotted Cophias (Cophias purpureo-maculatus), 
and the Beautiful Cophias ( Cophias ornatus). The last 
three are the most beautiful, and the most poisonous 
snakes of India. 
Other species with simple tails, have the head covered 
with large shield-like plates ( Trigonocephali ). 
The Vipers have the same broad head as the Rattle- 
Snakes, but have no pit before the eyes. Amongst 
these the True Vipers ( Viper os) are distinguished 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 ( Coluber nasicornis), peculiar for 
two horns on the end of the nose; the Cerastes ( Coluber 
cerastes'), the male of which has a long horn-like scale 
over each eye, which being absent in the female, has caused 
the latter to be erroneously described as a distinct species; 
the Puff Adder, or Short-tailed Viper ( Vipera injtata ), 
the most deadly snake of the Cape; and Russel’s Viper 
(Coluber Russell). 
The Adders (Beri) have the head covered with granular 
scales, and the nostrils moderate; as the Black Adder 
(Coluber beras), and the Ammodyte Adder (Coluber am- 
modytes) from the shores of the Mediterranean, very pecu¬ 
liar for the end of the nose being lengthened into a flexible 
horn. 
The Common Adder ( Coluber chersea ) differs from these, 
by the crown of the head having three larger scales in¬ 
serted amongst the smaller ones; this is the only reptile 
found in Great Britain possessed of dangerously poisonous 
qualities. 
The Cylindrical Snakes differ from the other venomous 
reptiles, by the head being much smaller, scarcely so broad 
as the body, 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, 
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 spectacles. These 
snakes are used by the native jugglers in their exhibitions. 
The Coral Snakes ( Elaps ) are very similar in form, but 
