THE FRESH WATERS 175 
there, wriggling farther in when disturbed. 
They take four years to reach their full size, 
and then, within a few weeks, they undergo 
the change to the adult form. 
The River Lamprey, which is still abundant 
in the Severn and some other English rivers, 
grows larger, and usually spends a part of its 
life in the sea. It used to be considered a table 
delicacy, and it was from the effects of too 
hearty a meal of these lampreys that Henry IT. 
is said to have died. They are still caught in 
considerable numbers, but are chiefly used for 
bait. There is a still larger Sea Lamprey, 
that spawns in rivers. 
FROM WATER TO LAND 
We shall find an instance of animals that 
seem to be on their way from fresh water to 
terrestrial life in a very familiar group—the 
frogs and toads, with their more distant cou- 
sins, the newts and salamanders. 
We need not go over the life-history of the 
frogs and toads, because any of us can watch it 
for ourselves, and it is very much better to see 
things than to read about them if it is possible. 
We have only to listen for the croaking of the 
