356 THE HISTORY OF CREATION. 
their specific form by superficial adaptation to particular 
local relations. 
Next to the flying animals, those animals, of course, have 
spread most quickly and furthest which were next best able 
to migrate, that is, the best runners among the inhabitants 
of the land, and the best swimmers among the inhabitants of 
the water. However, the power of such active migrations 
is not confined to those animals which throughout life enjoy 
free locomotion. For the fixed animals also, such as corals, 
tubicolous worms, sea-squirts, lily encrinites, sea-acorns, bar- 
nacles, and many other lower animals which adhere to sea- 
weeds, stones, etc, enjoy, at least at an early period of life, 
free locomotion. They all migrate before they adhere to 
anything. Their first free locomotive condition of early life 
is generally that of a “ciliated” larva, a roundish, cellular 
corpuscle, which, by means of a garb of movable “ flimmer- 
hairs,” (Latin, “ cilia”) swarms about in the water and bears 
the name of Planula. 
But the power of free locomotion, and hence, also, of active 
migration, is not confined to animals alone, but many plants 
likewise enjoy it. Many lower aquatic plants, especially the 
class of the Tangles (Algze), swim about freely in the water 
in early life, like the lower animals just mentioned, by 
means of a vibratile hairy coat, a vibrating whip, or a 
covering of tremulous fringes, and only at a later period 
adhere to objects. Even in the case of many higher plants, 
which we designate as creepers and climbing plants, we may 
speak of active migration. Their elongated stalks and 
perennial roots creep or climb during their long process 
of growth to new positions, and by means of their wide- 
spread branches they acquire new habitations, to which 
