408 THE INITABITANTS OF THE SEA. 
bulate the submarine meads, or to force his way leisurely through 
dense thickets of algae, and explore their hidden wonders. 
Yet, in spite of these natural impediments, his inventive 
genius, fired by his insatiable avidity of knowledge, has given 
him the means of interrogating the abyss, and partly raising the 
veil behind which marine life conceals its secret operations. 
Armed with a dredge, he fetches from the bottom of the sea 
plants, polypi, mollusks, and annelides, and learns to distinguish 
the various depths assigned for their abode; or he puts on the 
helmet of the submarine diver, and passes whole hours in collect- 
ing and observing beneath the clear waters of the sea; or he 
drops the plummet hundreds of fathoms deep into the ocean, 
and draws it up again coated with specimens of corals or Forami- 
nifera. 
To the late Professor Edward Forbes of Edinburgh science 
is indebted for the first investigations of this nature that have 
been undertaken on a greater scale; and, to give the reader 
some idea of the causes which regulate the distribution of marine 
life, I cannot do better than cite a few of the general results of 
that eminent naturalist’s researches.* 
As the animals and plants of the land are grouped together 
into distinct zoological and botanical provinces, so likewise is 
the population of the sea gathered into geographical groups, 
which, though well marked in their more central and most deve- 
loped portions, imperceptibly merge at their margins into those 
of neighbouring realms. “ These submarine provinces have a 
more or less direct correspondence with those of the neighbouring 
lands, though sometimes they differ very considerably from the 
latter in their extent; since the physical features which may 
constitute boundaries in the one, may not be sufficiently ex- 
tended or developed in the other to impede the spread of 
peculiar species of animals or plants. Marine creatures, owing 
to their organisation and the transporting powers of the element 
in which they live, are much more capable of diffusion, as a 
whole, than the terrestrial organisms; hence we should expect to 
find the regions they respectively inhabit, beneath the waves, of 
much vaster dimensions than those occupied by similar geogra- 
* Natural History of the European Seas, by the late Professor E. Forbes. Edited 
by R. Godwin Austen, 1859. 
