PROOFS OF EVOLUTION. 
47 
First, we will notice some of the living links to 
be found, not on account of Evolution, but in 
spite of it. These are cases mainly of retarded 
or arrested development, which will doubtless 
culminate at last in true types, the links finally 
disappearing. The most interesting group of 
synthetic types are the Amphibians — interesting 
because it explains how we got out of the water, 
and into the woods. The frog, whose transforma¬ 
tions have already been referred to, is the most 
familiar example of this group. The shores of 
the early seas were doubtless the scenes of many 
equally remarkable transformations. The creatures, 
ocean born, were brave and hardy fellows, and 
bent on becoming land-lubbers at any cost. All 
the Amphibians must be regarded as links between 
the true water animals and land animals. Their 
swim-bladders were made into lungs, their fins 
into legs, their scales into hair and feathers. 
The living link between the egg-layers and the 
milk-givers is the class of Marsupials, of which 
the Kangaroo is a familiar example, which bring 
forth their young in an imperfect state, the devel¬ 
opment being completed in a pouch in front. In 
fact, the entire fauna of Australia may be regarded 
