10 Fishery Board for Scotland. 



been taken by fishermen at various places round tlie Scottish coast 

 during spring, summer, and winter. 



Matthews found " that fishes of the same length and as nearly as 

 possible of the same bulk differed as to their dorsal and anal fins, 

 not only in the position of these relatively to the length of the body, 

 but that the fins themselves varied both as to the length of their 

 bases and also in respect to the respective lengths of the individual 

 rays measured from their bases to their tips ; a circumstance due 

 not only to the different amount of wear they had undergone, which 

 is probably slight, but also to absolute difference in the amount of 

 their development, increased, as it likely is, by the difference in age 

 of the fish. In several cases it was clear that the length of the caudal 

 fin was affected by wear or by injury received after the capture of 

 the herring. But a far greater difference was found in the actual 

 length of the caudal fin-rays as measured from their proximal ends, 

 and also from the termination of the intervening and supporting 

 hypural bones in herrings as nearly alike as possible in the length 

 and bulk of their bodies." 



" It was evident also that the fishes were subject to very con- 

 siderable variation in the position of the lobes of the caudal fin, 

 caused aj)parently by the amount of muscular contraction after 

 death, and as a consequence of this, there of course resulted a con- 

 siderable degree of variation in the total length of the fish (sometimes 

 as much as 10 mm.), according to whether the lobes were approximated 

 so as to be nearly in a straight line behind the body, or were widely 

 spread." 



" The depth of the mature herring caught during or near to the 

 time of spawning is almost wholly influenced in its extent by the 

 condition of the reproductive organs, and so many variable degrees 

 of these are found that any measurement of the depth of the body 

 proper is most unsatisfactory as a test of the size of the fish. There 

 is, however, a point which gives a fair index of the size of the fish 

 in this respect, and which is but very little affected by the size of 

 the generative organs. This is the depth of the fish at the anterior 

 end of the body in a line with the back of the head, the upper point 

 being fixed by the dorsal surface of the supra-occipital bone, the 

 lower by the ventral edges of the clavicles." 



Size of the Fish. — " We can scarcely distinguish, as regards size, 

 the herring of any particular locality, or perhaps even seasons, by a 

 preference over the others without further confirmatory evidence, 

 such as miglit be brought out by an examination of differences in 

 other characters and the common presence of one or more of such, 

 specially in the fish of any one place or season. 



Length of the Head. — " The measurement of the length of the 

 head in comparison to the total length is extremely variable. If we 

 do not consider the slight difference in total length found between the 

 winter- and summer-herrings sufficient to indicate a distinct variety, 

 neither is there stronger evidence from the length of the head."' 



Position of the Pectoral Fin. — " There seems to be little difference 

 in the position of this fin on the summer- and winter-herrings, the 

 winter-fish having it, if anything, slightly farther back than the summer- 

 fish." 



Position of the Pelvic (Ventral) Fin. — " The pelvic fin of the winter- 



