of tlic Fishcrtj Board for Scotland. 



379 



respectively. This might be due to some extent to difference of rate of 

 gi-owth in the two localities ; but the curve for the fish from the deej^er 

 water is rather better than the other. 



The apparent increment of growth of the fishes in the group, as shown 

 by these averages, is 33-5 mm. from 10th May to 24th July (75 days), 

 and 8-3 mm. from 24th July to 19th August (27 days), or a total increase 

 in the 102 days of 41*8 mm., or 1| inches. The corresponding increase 

 in the same period at Station III. was very nearly the same, viz. 

 7'9 mm. and 32-9 mm., the total being 40*8 mm., or only 1 mm. 

 less than the other. The number of fishes on which the former 

 calculation is based was 1675, the number in the latter case being 1342, 

 and the close agreement of the mean increase in the two cases proves, I 

 think, that the amount of growth indicated very closely approximates to 

 the truth. 



Comparison of the avei-age size for this and the preceding group in 

 the various months shows an apparent annual rate of growth as 

 follows : — 



Larger series were present in these Forth hauls, but as usual the 

 difficulty of differentiating some of them is considei'able. The third 

 group at the inner station in May was imperfectly represented. It 

 comprised forty-five females varying from 159 to 201 mm., and having 

 an average length of 183' 7 mm., and fifteen males from 138 to 189 mm., 

 with an average of 172'3 mm., the average for the combined group being 

 180'9 mm., or 7g inches. These averages are too large to represent 

 accurately the real mean-size of the group. On June 20th twenty- 

 seven females of this series had an average size of 178"6mm., and a 

 r.ange from 154 to 208; and seven males varying from 151 to 198, 

 and possessing a mean length of 171 "9 mm., the average for the group 

 with the sexes combined being 177'2mm., or 7 inches., i.e. less than 

 in May. On 24th July the average for the combined group, comprising 

 twenty-nine fishes, appeal's as 177*8 mm.; on 19th August it was 

 183'5 mm. for 35 fishes, the mean length of the females being 190'9mm., 

 and of the males 158*4 mm. The same series on 22nd August had an 

 average size of 190*6 mm. for females — twenty-eight in number — and 

 173*7 for three males, and the averages for this series in the August 

 hauls combined are for females 190*8 mm., with a range of from 155 

 to 213 mm., and for males 162*5 mm., ranging from 137 to 188 mm., 

 the average for the group with the sexes combined being 186*1 mm., or 

 7yy inches. 



At the outer station in May this series, imperfectly represented, 

 comprised 32 males and 90 females, the mean length of the former 

 being 169*5 and the range from 143 to 185 mm., while the males ranged 

 from 125 to 179 mm., and had an average of 149*1 mm. The average 



