FLAT-SIDED AND FLAT-BACKED FISHES 405 



coloured, but the colour of all flat fish varies a good deal with 

 the ground on which they lie, so that nothing dependable can 

 be said on that point. 



PLAICE (Pleuronectes platessd) may always be identified by 

 their red spots. They are fairly plentiful all round our coasts, 

 and in places afford really good sport to the sea angler. Like 

 most other flat fish, they haunt sandbanks and muddy bottoms, 

 and may often be found in quantities on sandy patches sur- 

 rounded by rocks. I have caught them in three fathoms of 

 water, or less. 



A very perfect mare's nest was once discovered in con- 

 nection with these fish. The theory was started that they 

 were descended from shrimps, and a naturalist, to test the 

 statement in a praiseworthy practical manner, obtained a few 

 live shrimps and kept them in a tank. At the end of a 

 few days he found in the tank some young plaice, and 

 further investigations tended to show that the eggs of the 

 plaice were sticking to the shrimps when placed in the 

 little aquarium. In the following year he half filled two 

 vessels with salt water, making one the home of a few plaice, 

 devoting the other to plaice and shrimps. In both vessels the 

 plaice spawned, but only in the vessel containing the shrimps 

 did the ova hatch. So the experimenter came to the conclu- 

 sion that in some way the shrimp was essential to the hatching 

 of a plaice egg. Since that day, however, plaice eggs have 

 been hatched in -the laboratory of the Marine Biological Asso- 

 ciation at Plymouth and other places, and this without the 

 assistance of shrimps. 



Plaice are fished for on the bottom with such tackle as 

 that shown on p. 243, and many more will be caught if a rod 

 is used than on a hand line. I prefer a hook about half the 

 size of those used by the fishermen, baited with lugworm, 

 mussel, ragworm, peeled uncooked shrimp, cockle, or any soft 



