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A NATURAL HISTORY OF THE SEAS 



In the Sail Fish (Isthiophorus) — a fish built on mackerel lines 

 — the dorsal fin is of enormous size and forms a huge sail, 

 which is folded away in a groove when not in use. 



In the Shark-suckers or Remoras (Echenius) the first 

 dorsal fin is transformed into an oval sucking disc, the spines 

 forming a double series of transverse plates surrounded 

 by a fleshy fringe, and the erection of the plates results in 



Shark-suckers or Remoras 



a series of vacuum chambers. By means of this powerful 

 disc the Shark-sucker securely anchors itself to the back, 

 sides or undersurface of a shark, where it battens on such 

 fragments of food as are always in evidence when a shark 

 tears at its prey. 



So well known is this fish's curious trait that from 

 early times the Shark-sucker has been utilised by native 

 fishermen to aid them in the chase. One or more are put 

 over the sides with long lines attached to their tails. The 



