THE HERRING 139 



is far better, and as fresh herrings are very easily procured 

 in the season, I will suppose that we have one before us. 

 We remark first the general shape of the body, the rounded 

 back with its single dorsal fin, the forked tail-fin, in front 

 of which, on the ventral side, comes the anal fin. Between 

 this and the head the belly thins out to a sharp edge, and 

 is serrated by a number of bony plates, each of which has 

 its own keel. There are two paired fins, answering to the 

 fore and hind legs of a quadruped, or to the arms and legs 

 of man ; the front pair (pectoral fins) are set just behind 

 the head, while the hind pair (ventral fins) come beneath 

 the fore part of the dorsal fin. The fins of a herring are 

 supported by bony rays, which are soft and flexible, each 

 being made up of a series of small joints ; stiff spines, like 

 those which support the dorsal fin of a perch, or stick out 

 in front of the dorsal fin of a stickleback, are altogether 

 wanting in the herring. All parts of the body except the 

 top of the head are covered with thin, flexible, silvery 

 scales, which are so easily rubbed off, if we pass the finger 

 from the tail to the head of the fish, that we might suppose 

 them to be quite loose. They are not really loose ; a 

 delicate transparent membrane overlies them all and forms 

 a sheath to every one. This membrane is the proper 

 epiderm or outer skin-layer, and the scales lie within it, 

 being formed from the derm or deep skin-layer. The 

 scales of fishes have therefore a different origin from the 

 scales of a snake, or the scales on the feet of birds, which, 

 are truly epidermal, and not dermal. The large eyes 

 cannot be closed, but are slightly protected by transparent 

 folds, something like eyelids ; the eyelids of the herring, 

 however, are not upper and lower, but fore and hind ; the 

 opening between them is vertical, and cannot be enlarged 

 or diminished. 



If you force open the mouth of a fresh herring, you will 

 find that the upper jaws are pulled downwards when the 

 lower jaw is depressed, as if to prevent small objects 

 escaping from the sides of the mouth. The gape is not 



