234 SALT-WATER FISHES 



The Norwegian Topknot (Z. norvegicus'), smallest of 

 the three and mature already when only 3 in. long, is 

 commonest in the Channel, but does not extend much 

 farther south. It is less rough to the touch than the others, 

 and the front ray of the dorsal fin is not long, as in the 

 last species. 



The egg measures rather under -^^ in., not -^ in. 

 as Cunningham gives it, an obvious misprint, since 

 he gives the correct measurement in millimetres. {A.t 

 -^ in. the egg would be half again as large as the salmon's, 

 rather a remarkable feat for a fish 3 in. long, and one that 

 would make it a very kiwi among fishes !) 



Soleidae 



Of the Soleidtt, the second family of flat-fish as at present 

 classified, one is the most important of the whole sub-order, 

 and three closely related forms are neither familiar nor 

 valuable. 



These fishes have several peculiarities which serve to dis- 

 tinguish them from all the flat-fish hitherto enumerated. In 

 the first place, they have teeth only on the underside, and the 

 mouth is more twisted and smaller than even in the plaice, 

 which approaches nearest to their condition in this respect. 

 The twist of the mouth gives the snout a curious projecting 

 appearance, which develops in large examples into a hook. 

 This may be seen by no more than a casual glance at the soles 

 lying on the fishmonger's slab. As another distinction, the 

 lower side of the head has a kind of beard, while the eyes are 

 small, and the dorsal fin commences in front of them. 



The Sole (^Solea ■vulgaris) has all these characters, and is too 

 familiar a fish to need any detailed description. In colour it 

 is a variable brown above, with darker streaks or blotches, and 

 white below. The upper side is, however, subject to great 



