GROWTH AND KEARING OF FOOD-FISH. 371 



same as in tlie next tank, which contained an overflow pipe. In this 

 way a constant flow of water was maintained in the tank without 

 causing any strong current at the outflow, so that the small fish 

 could neither escape nor be injured by a strong current of water 

 towards the outflow. 



I fed these young fish at first with minute Crustacea, procured by 

 sifting a quantity of weeds from the shore in water. In this way 

 numbers of small Copepods, Amphipods, and Isopods were separated 

 from the weeds, and were then put into the flounder-tank. The 

 little fish took this food eagerly, but the labour of preparing it was 

 considerable. I therefore soon gave up this method, and fed the 

 fish with chopped worms {Nereis, Nephthys, &c.). The minced worms 

 were strained through a vulcanite sieve, and only the smaller 

 particles were given to the young fish. As the fish grew older 

 other kinds of food, such as chopped Pecten and pilchard, were occa- 

 sionally given, but the fish always took worm with most eagerness. 

 During my absence from the Laboratory between July 1st and 

 August 13th the fish were regularly fed by the attendant, and on 

 my return I found that they were all in a healthy condition, and that 

 they had grown very considerably, although the size of different 

 individuals varied very much. On August 19th, of two specimens 

 from the tank in the aquarium one measured 6*7 cm. (2|^ inches) in 

 length, the other 8 cm, (3y\ inches). These specimens were not the 

 largest in the tank, but I believe that they were above the average 

 size of the whole number. As the fish are very active, and always 

 more or less concealed by the sand, it is, of course, impossible to 

 ascertain the minimum and maximum size, or the average size, with- 

 out killing the whole number. But it is clear that in three and a 

 half months many of these fish have grown from about ^ inch in 

 length to 3 inches. 



The Brill {Rhombus leevis, Gottsche). — On May 21st of the current 

 year boys and fishermen brought to the Laboratory a number of 

 the young of this species. They were found swimming near the 

 surface of the water in Sutton Pool, and were taken out either by 

 hand or with a tin pot. There had been a south wind on that and 

 the previous days, and the fish were found at flood tide. I put 

 twenty of these into the tank in the aquarium, where the young 

 flounders were. 



On June 11th I received fourteen more of the same species in 

 about the same stage. Those placed with the flounders were 

 observed to catch and devour them, so that I had another tank 

 prepared after the same fashion, and placed all the brill in this by 

 themselves. I could only find seventeen in the flounder-tank, so 

 that the total number of brill isolated in the tank devoted to them 



