INTRODUCTION 31 
like Gomontia (Fig. 50), which bore into and inhabit 
shells. The whole of the investing substance may be 
thus removed, and the Alga disclosed without any 
breaking up of its filaments or injury to its cells. In 
other respects the ordinary methods of microscopical 
examination are sufficient. 
In considering the economic uses of seaweeds, the 
indirect service they render as the basis of the nutri- 
tion of animal life in the sea, and consequently their 
fundamental importance for fishery, must not be left 
out of account here, as it practically has been by 
fishery boards and others whose main concern it 
might appear to be. In investigating the food of 
fishes, the so-called practical inquirer is accustomed 
to look no further than the immediate organisms 
eaten, much as if in agricultural matters no heed 
were given to the pasturage of farm stock. There is 
no doubt that the enormous shoals of Peridinice and 
other allied free-floating Algz are the pastures on 
which the organisms constituting the food of fishes 
themselves feed—that in fishery matters they are the 
basis of the pyramid of which man is the apex, and 
the dearth of knowledge of these forms and the indif- 
ference of fishery authorities to the subject in its 
technical aspect, is only equalled by the ignorance 
and apathy of botanists towards its scientific value. 
The direct economic importance of Alge is no 
longer so great as it was early in the present cen- 
tury, when the kelp industry flourished in the north 
of Scotland and the western coasts of Scotland and 
Ireland. The value of kelp in the manufacture of 
soap and glass became greatly enhanced by the 
