PREFACH 
TO 
THE THIRD AND FOURTH EDITIONS. 
Nortuine can be more agreeable to an author anxious to 
merit the suffrages of the public, than the opportunity 
afforded him, by a new edition, of correcting past errors 
or adding improvements to his work. Should any one of 
my readers think it worth his while to compare ‘ The 
Sea,’ such as it now is, with what it formerly was, I have 
no doubt he will do me the justice to say that I have 
conscientiously striven to deserve his approbation. 
Two new chapters—one on Marine Constructions, the 
other on Marine Caves 
have been added; those on tke 
Molluscs and Ccelenterata (Jelly-fishes, Polyps) almost 
entirely re-written; and those on Fishes, Crustaceans, 
Microscopic Animals, the Geographical Distribution of 
Marine Life, and the Phosphorescence of the Sea, con- 
siderably enlarged; not to mention a number of minor 
improvements dispersed throughout the volume. 
Great attention has also been paid to the Illustrations, 
many of questionable value having been omitted in the 
present edition, to make room for a number of others, 
