36 



THE FISHERIES OF THE ADRIATIC, 



In the second instance, — 



horizontal distribution, 

 limited extended 



extended vertical distribution in the Ouarnero 27 9 



limited to one zone 103 27 



both of.which results (we quote Dr. Lorenz) would speak against the theory 

 of Professor Forbes (a theory which in the case of Alga; is fully borne out), 

 viz., — that an "extended" vertical distribution speaks, at the same time, for an 

 "extended" horizontal distribution, and vice versa. 



At any rate, the greater number of species, which, according to this 

 theory, should have an "extended" distribution, belong, on the contrary, to 

 the "limited" distribution in whichever sense we chose to comprehend the 

 term "limited"; on the other hand, however, it is fully borne out in the 

 instance of some species, such as, — Ophiotrix fragilis, Asteracanthion 

 glacialis, Echinus microtuberculatus, Xantho rivulosus, and Portunus Rondeletii, 

 which are distributed throughout most of the zones, and have, likewise, a 

 wide horizontal distribution, even as far as the Indian Ocean and the Arctic 



The lower we proceed the higher becomes the percentage of Northern forms. 

 The following table shows the horizontal distribution of those species 

 whose o-eneral distribution is known : — 



1 Of which 4 are almost exclusively Boreal. 



2 Of which 3 ditto . ditto. 



8 Of which 3 extend to the Arctic regions. 



