146 LEMON SOLES 



upon to undergo ! ' Little difficulty ', says Mcintosh. ' would be 

 encountered in hatching and rearing it under artificial circum- 

 stances.' The rate of development, no doubt, like the rate of 

 mcubation, varies with temperature, and again we are without 

 very badly needed data ; but in the case of the fish described 

 by McLitosh, which were in water of a temperature not recorded, 

 the yolk had much diminished on the third day. On the fourth 

 day the mouth was gaping without any movement of the jaws. 

 Neither McLitosh nor Meek tells us how many days passed before 

 the complete absorption of the yolk, but the latter writes that 

 at that time the larvae measure about 0-21 inch (5-5 mm.). 



The Post Larval Fry 



Cunningham's fry lived to the eleventh day. There is no 

 record of any attempt to feed them before the absorption of the 

 sac, and no information as to what constitute favourable or 



Fig. 16. — Baby lemon sole 0-25 inch (6-5 mm.) long. (Drawn by Dr. M. V 

 Lebour.) 



unfavourable circumstances during this all-important critical 

 period. Clark this year obtained at Plymouth nineteen little 

 lemon soles, varying from 6 to 18 millimetres in length. All 

 these were still floating at the surface. Dr. Lebour dissected 

 nine little fish ; the smallest of these was 7 millimetres long 

 and had been feeding on the eggs of some copepod ; two of 

 8 millimetres contained no perceptible food. At 9 milhmetres 

 they were feeding on the free-swimming larva of the copepod 

 Temora, and up to 19 millimetres no food was found in them 

 except the eggs and larvae of copepods. Her previous records 

 ' show many specimens with no food, and what there is consists 

 chiefly of very small Crustacea and unicellular organisms. It 

 seems evident that Pleuronedes ^nicrocephalus is incapable of 

 eating any large copepods, and that its diet up to the time of 

 metamorphosis consists of very small organisms, its food being 

 more hke that of the flounder than of the dab and soles.' ^ 

 The newly-hatched flounder is more or less of a vegetarian. 



' Journ. M. B. ^., N. S. xii, No. 2, p. 294. 



