92 FRESH-WATER ALG^. 



To many others I might also confess myself indebted for valu- 

 able information as to the influence of Darwin's work on biology 

 as a whole ; but my special and grateful thanks are due to three 

 authors, from whom I have gleaned many facts, and whose words 

 I have largely quoted. I refer to Mr, Romanes, the writer of 

 ' Charles Darwin ' in the ' Nature Series ' ; to Mr. Woodall, for 

 his Memoir issued in the ' Transactions of the Shropshire Archae- 

 ological Society ' ; and most of all to Mr. Grant Allen, the author 

 of the lately published book, ' Charles Darwin ' in the series of 

 ' English Worthies.' 



Referring to Darwin's work in Geology, and more especially to 

 his work on Coral Reefs ^ on page 82, I wish to add that I used 

 the words, " recognized classic in geological literature " quite 

 advisedly ; but it is only right to advert to the fact that the more 

 recent researches of Murray and Agassiz in 1880 and 1883 respec- 

 tively would appear to force us to conclude that we cannot now 

 accept Darwin's theory as offering a complete solution of the 

 problem of these reefs. For an admirable digest of the researches 

 of the naturalists above named, I refer my readers to the two 

 papers on the Origin of Coral Reefs, by Professor Geikie, in 

 Nature, vol. xxix., pp. 107 and 124. 



H. W. S. W-B. 



By George Norman, M.R.C.S., &c. 

 Part II. 



Plates 9, 10, 11. 



Class I. — Protophyta. 



IN this class we commence with the simplest form of plant-life 

 — a little mass of protoplasm, with or without a cell wall. The 

 cell-wall is usually to be found, but when the plant assumes an 

 amoeboid condition the cell-wall is absent. An example of this is 



