140 HOUSE, GARDEN, AND FIELD 



wide, nor is it necessary that it should be, for the herring 

 feeds upon minute Crustacea which swim at the surface 

 of the sea, and its mouth has very naturally quite different 

 proportions from those of such a fish as the pike, which 

 pursues large animals. The teeth of a herring are so small 

 that they can hardly be seen without a magnifying glass ; 

 there is a patch of them on the roof of the mouth, and 

 another on the tongue, both of which are more easily felt 

 than seen. 



The herring has particularly open gills, and a large, 

 smooth gill- cover. Raise the gill- cover, and look at the 

 gills, row behind row of soft red filaments. The wide 

 gill-clefts make it possible to capture herrings, pilchards 

 and mackerel by the drift-net, which is a long net hung 

 vertically at the surface of the sea. In trying to force 

 their way through the net they get meshed, the gill-covers 

 catch, and the fishes are held fast. 



From a herring or any other fish which has been boiled 

 you can easily extract the lens of the eye a small hard 

 globe, white in a boiled fish. Why is the lens, which is 

 flattened in man, sheep and ox, globular in a fish ? Because 

 of the high refractive power of water. There is little 

 difference between the refractive power of water and that 

 of the substance of the lens, so the curvature of the surface 

 must be very great in any animal which has to see under 

 water. 



In the head of a herring you will find a pair of hard 

 white otoliths. They belong to the inner ear, and in some 

 way that we very little understand serve to increase the 

 power either of hearing or of some other sense. They are 

 more easily extracted from the head of a large fish, such 

 as a cod or a haddock. The ear in the herring or any 

 other fish has no passage by which the vibrations of the 

 water can be directly transmitted, and of course there is 

 no drum in such an ear. The powerful vibrations set up 

 in water can pass even through bones and flesh. There 

 is no doubt that herrings can hear. Huxley tells us, in 



