204 Part III. — Twenty-fourth Annual Report 



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The outstanding feature of the above Table is that a line drawn 

 diagonally from the top left-hand corner (at January) to the bottom right- 

 hand corner divides the small brill into two groups, an upper and a lower; 

 and the inference is that those below the line in April, May, and June 

 are a full year or more in age. 



Before considering this Table further, reference may be made to some 

 experiments by Cunningham in rearing young brill in tanks. He placed 

 the 34 specimens, measuring from 22mm. to 25mm., taken between 21st 

 May and 11th June, and above mentioned, in an aquarium. He 

 computed their age to be about three weeks or a month. On 18th 

 October following four of them were measured, and their length was found 

 to be from 70mm. to 98mm. (2|-3§ inches), the growth of these four, in 

 the 140 days or so that elapsed, amounting to about 60mm. — or, to give 

 the extremes, to from 45mm. to 76mm. The author does not state 

 anything as to the sizes of the others, except that on 4th October one 

 measured 85mm. ; nor is the temperature given, but it is obvious that 

 the period comprised the chief season of growth. Other two of these 

 brill w r ere measured on 3rd April in the following year, and their lengths 

 were respectively 84mm. and 88mm. (3J-3| inches), giving an approxi- 

 mate increase from the beginning of June in the previous year, or in about 

 307 days, of only 6cm., or 2| inches. These fish were nearly one year old. 



Cunningham suggests a.s a reason for the slow growth, which he thinks 

 had been abnormally checked, that they were fed on marine worms and 

 not on living fish ; but it is much more likely that it was chiefly owing 

 to the lowered temperature of the water in winter. I have already shown 

 that small plaice at the same stage, which frequent the same habitat on 



