88 THE HAUNTS OF LIFE 
has weighed some up to 940 Ib. and measured 
some up to 7 feet in length. All these are 
doubtless the descendants of land tortoises, 
for they breathe dry air as terrestrial animals 
do, and they give away their secret in the fact 
that they all come to the shore to lay their 
eggs in the sand. Animals that have found a 
new kind of home usually go back to the old 
home to breed. Whales evade this law be- 
cause the mother carries her young one for a 
long time before birth, so that when it is born 
it can swim for itself. 
SEA-SNAKES AND SEA-SERPENTS 
Turtles have their legs flattened into flip- 
pers,—the oars by which they swim; whales 
have their fore-limbs flattened into flippers, 
which are chiefly used in balancing, the pro- 
peller being the tail; snakes have no limbs, 
but it is interesting to find that the sea-snakes 
show a marked flattening in the tail region, 
and sometimes in the posterior part of the 
trunk as well. In all cases the meaning of the 
flattening is the same; it is an adaptation 
which secures a good grip of the water. The 
sea-snakes are mostly fish-eaters, and very 
