204 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



If we compare the young herring .(figs. 13 and 14) 

 and the two young sprats (figs. 15 and 16) with the illus- 

 trations representing the first three samples, it can easily 

 be seen that the fish captured on March 11th and 31st and 

 on April 16th are young herring. The fish caught on 

 March 11th measured 347 to 45'7 millimetres in length. 

 The next lot taken on March 31st were probably part of 

 the same shoal that visited the strait nearly a fortnight 

 earlier, as the measurements are practically the same. 

 Those caught on April 16th probably belonged to a later 

 hatching than the first two samples, as they are 

 distinctly smaller fish. Their size ranged from 33*7 to 

 40'7 millimetres. It is scarcely likely that they belonged 

 to the same shoal represented on March 11th, as we would 

 naturally expect larger fish after fully a month's longer 

 time to grow. It will be noticed on looking over the 

 column giving the difference in the pelvic fins that the 

 variation is by no means uniform. Generally, however, 

 the variation in the pelvic fins is greater in the smaller 

 fish than in the larger ones. This ought to be the case if 

 the dorsal fin moves forward as the fish grows. The 

 sample taken on May 14th consisted of a mixture of young 

 herring and sprats. Fig. 4 shows one of the herring. The 

 whole of the fish captured on May 28th were young 

 herring from 42"6 to 67'3 millimetres in length. Figs. 11 

 and 12 show the largest and smallest fish in this 

 catch. The small one is nearly the same size as the largest 

 fish caught in April, and it is evident that the 

 collection contains at least two distinct generations of 

 herring. The fish caught on June 29th were apparently all 

 sprats, measuring from 23'6 to 43'6 millimetres in length. 

 The sample taken on July 17th contained ninety-seven 

 fish. Eight of them were young herring from 33'7 to 38*9 

 millimetres. The remainder were sprats from 37'3 to 53'6 



