of the Fisher y Board for Scotland. 



315 



herring as well as to the probable variability in size and age of its parents. 

 The embryo herrings themselves vary considerably in size on hatching, 

 even among ova from the same fish, and Meyer's observations* show how 

 the matter of food affects their growth ; this would especially affect their 

 ultimate size. In regard to the absolute size of the herrings the largest 

 example I was able to quote in the former part of this piper as having 

 received was 333 mm. (13|-") in length from tip of the lower jaw to tip of 

 the caudal fin. Mr Brook, f who considers there are two if not more races 

 of herrings in Loch Fyne alone (and if these are not considered to be 

 permanent and established varieties, it seems to me likely to be correct), 

 refers to the size of these — indistinguishable from one another in the early 

 part of the season, later one race is of the moderate size of 10" while the 

 other increases to an average size of 12", while some of the latter are 15" 

 in length. It does not seem clear why the 10" May herrings should be con- 

 sidered as of a different race from the 12" August herrings, size alone 

 being, I think, an insufficient proof. What I have, however, specially to 

 refer to is the remarkable size of these August fish — a size I think which 

 must be considered as quite exceptional. The specimens which I have 

 examined from the same locality during the season in question, were few 

 in number, and cannot therefore be considered a fair test, but during other 

 three seasons I have never found the herrings in general so large as to give 

 an average of 1 2", the production of which must necessitate a very large 

 number much above that size. In regard again to the huge 15" herrings 

 recorded by Mr Brook, they are far beyond any specimens measured by 

 me, collected although these have been during three years from every east 

 and west coast district. Since the former part of my paper was written, 

 i.e., during last summer and autumn, I have measured a further large 

 number of herrings, mostly from the west coast, but have only succeeded 

 in finding one — from Campbeltown — which reached as much as 335 mm. 

 (13^") in total length. Mr Brook's statement then being taken as 

 correct, my original account of the probable limit of length of our herrings 

 must be modified, but I should still think the size of the large numbers 

 which have been accurately measured by me, is evidence that those of a 

 larger size are rare. 



Finally, in considering the variations of the different characters referred 

 to in this paper, it ought to be remembered that these variations, although 

 seeming considerable in regard to the ratio which they bear to the body 

 length, are not in absolute dimensions so very great ; and from occasional 

 measurement and examination of similar features in many other kinds of 

 fish, I believe them not to be at all peculiar either in extent or in kind to 

 the herring — many fish indeed, about the single specific character of which 

 no doubt has been expressed, often showing greater variation. It is from 

 these observations that I would deprecate the not uncommon circumstance 

 of an observer putting down as erroneous the record by previous observers 

 of particular characters which do not agree with his own. This would 

 not occur if due allowance were made for the probable variation which 

 generally obtains. The interest of such differences in statement should 

 wholly lie in the effect which they would have in showing the amount of 

 variation occuring in every species, and by the inclusion of a large number 

 of examples, the more correct ascertainment of their more normal condition. 

 The only proof, where the suspected racial difference is so obscure as in 

 the herring, I think would lie not only in a distinct demarcation between 

 two forms of character, however narrow it might be, but where by 

 prolonged investigation over recurring seasons or in distinct localities the 



* Jalirsbericht der Com. z. IVissench. Untcrsuch. dcr Deutschcn Mecre, 1878, 1882. 

 t Fourth Annual Report of the Fishery Board for Scotland, 1886. 



