The American species (Boa) have only a 
single row of plates beneath the tail; they vary 
greatly in the structure of the scales on the 
head and lips. 
Some of the Indian species, as the Netted 
Boa, (Boa regia,) have a single series of plates, 
whilst most of the other species have two rows 
(Python) ; as the Javan Boa (Col. Javanicus ), 
and the Tiger Boa (Col. boqformis). The 
Eryx differs from the other Boas in having a 
cylindrical body, a very short tail, and the head 
covered with scales similar to those of the back. 
Baron Cuvier, by some oversight, says that 
this genus has no spurs, but the Museum speci¬ 
men shews them distinctly. 
The Sea-Snakes (Hydrus) are easily known 
by their compressed form, narrow ventral shields, 
and the vertically flattened tail. They are only 
found in the seas of Asia and New Holland, 
and many of the species are provided with small 
fangs, dispersed amongst their teeth. These 
reptiles are, to a certain degree, poisonous. 
Some of these species have a small head and 
the body covered with scales ( Hydrophis ), as 
the larger Sea-Snake (Hydrus major) ; the 
others have a large head and a broad neck, and 
the body covered with embedded square piates 
placed in longitudinal series; as the Banded 
Sea-Snake (Pelamis fasciatus ), and the two- 
coloured Sea-Snake (Pelamis bicolor ). 
f 2 
The 
