HABITS OF SEA SNAKES. 157 
sempert), which is only found in a fresh-water lake at Luzon, in 
the Philippines. 
The Sea Snakes can be distinguished com all other snakes by 
the flattened oar-like tail, which is used as a rudder and propeller, 
for they have no fins. 
Sea Snakes shed their skins very frequently, but the old skin 
Shull of Hydrus platurus. 
Fic. 66.—Skulls and poison fangs of Black and Yellow Sea Snakes (Hydrus platurus). There 
are two fangs in each jaw (Brit. Mus. Cat. Snakes.) 
peels off in pieces, and does not come away entire, as is the case 
with their terrestrial cousins. 
HABITS OF SEA SNAKES. 
Although living in the water, they breathe air. Their nostrils 
are situated on the top of the snout. Most species are brilliantly 
and beautifully coloured. Their food is fish and other marine 
creatures. Although most species are helpless, and perish if cast 
