84 THE HISTORY OF CREATION. 
such species as the minute Protococcus, several hundred 
thousands of which occupy a space no larger than a pin’s 
head. At the highest stage we marvel at the gigantic 
Macrocysts, which attain a length of from 300 to 400 feet, the 
longest of all forms in the vegetable kingdem. It is possible 
that a large portion of the coal has been formed out of Algze. 
If not for these reasons, yet the Algz must excite our 
special attention from the fact that they form the beginning 
of vegetable life, and contain the original forms of all other 
groups of plants, supposing that our monophyletic hypo- 
thesis of a common origin for all groups of plants is correct. 
(Compare p. 83.) | 
Most people living inland can form but a very imperfect 
idea of this exceedingly interesting branch of the vege- 
table kingdom, because they know only its proportionately 
small and simple representatives living in fresh water. The 
slimy green aquatic filaments and flakes of our pools and 
ditches and springs, the light green slimy coverings of all 
kinds of wood which have for any length of time been in 
contact with water, the yellowish green, frothy, and oozy 
growths of our village ponds, the green filaments resembling 
tufts of hair which occur everywhere in fresh water, stag- 
nant and flowing, are for the most part composed of dif- 
ferent species of Algz. Only those who have visited 
the sea-shore, and wondered at the immense masses of 
cast-up seaweed, and who, from the rocky coast of the 
Mediterranean, have seen through the clear blue waters the 
beautifully-formed and highly-coloured vegetation of Algze 
at the bottom, know how to estimate the importance of the 
class of Alew. And yet, even these marine Alge-forests 
of European shores, so rich in forms, give only a faint idea 
