FISHES. 329 



their voracity, and have been termed "mere machines for 

 the assimilation of other organisms." 



Among the marine members of the order are the her- 

 ring (fig. 128), shad, menhaden, fishes of great importance 

 to man, both as food and for the oil and fertilizers which 



FIG. 128. Herring (Clupea harengus). 



are made from them. They occur in large schools, and 

 afford food for numerous predaceous fishes. 



Differing from the forms already mentioned are those 



V 



which may be grouped together as eels, fishes with elongate 

 bodies and without ventral fins. Most of the species are 

 marine, and those which live in fresh water go to the sea 

 to spawn. All are voracious creatures, and one South 

 American species has marked electrical powers. 



ORDER II. ANACANTHINI. 



These have the gills comb-like (p. 327) ; the dorsal, anal, 

 and ventral fins without spines; the ventral fins, when 

 present, placed far forward between the pectorals; the 

 swim-bladder without connection with the gullet; and the 

 scales either ctenoid or cycloid. Mostly marine. 



J / 



But few of these forms need mention. Most important 

 of all are the cod (fig. 129) and haddock, which stand 

 beyond all others as food-fishes. They occur in the north- 



