6 THE DEPTHS OF THE SEA. [CHAP. I. 
to the distribution of marine forms. ‘The remainder 
of the book is a continuation by his friend Mr. Godwin 
Austen, for before it was finished an early death had 
eut short the career of the most accomplished and 
original naturalist of his time. 
I will give a brief sketch of the general results 
to which Forbes was led by his labours, and I shall 
have to point out hereafter, that although we are 
now inclined to look somewhat differently on certain 
very fundamental points, and although recent inves- 
tigations with better appliances and more extended 
experience have invalidated many of his conclusions, 
to Forbes is due the credit of having been the first to 
treat these questions in a broad philosophical sense, 
and to point out that the only means of acquiring a 
true knowledge of the rationale of the distribution of 
our present fauna, is to make ourselves acquainted 
with its history, to connect the present with the past. 
This is the direction which must be taken by future 
inquiry. Forbes, as a pioneer in this line of research, 
was scarcely in a position to appreciate the full value 
of his work. Every, year adds enormously to our 
stock of data, and every new fact indicates more 
clearly the brilliant results which are to be obtained 
by following his methods, and by emulating his 
enthusiasm and his indefatigable industry. | 
Forbes believed implicitly, along with nearly all the 
leading naturalists of his time, in the immutability 
of species. He says (Natural History of the British 
Seas, p. 8), ‘‘ Every true species presents in its indi- 
viduals, certain features, specific characters, which 
distinguish it from every other species; as if the 
Creator had set an exclusive mark or seal on each 
