78 



Appendices to Fourth Annual Report 



separate varieties or races as regards these characters unless we find either 

 a special peculiarity in respect of one character prevalent in any one place 

 or at any one season, and conspicuous by its absence elsewhere, or else if 

 we find two or more, perhaps not so strongly marked characters generally 

 present together, and limited to the fish of a particular locality. Now, in 

 order to ascertain in what manner and to what extent any of the many 

 variable characteristics of the herring are found in combination a very 

 extensive and minute examination of the condition of these in each 

 single fish is requisite ; and then is required a reduction of the almost 

 certainly large number of combinations into more broad general classes, 

 and the application of these to localities or seasons. 



This part of the investigation is not yet complete, and we can meantime 

 only view each character as it is represented on the herrings as a whole 

 body, and in particular localities or seasons, but not in its relation to the 

 other characters on each individual fish. 



A very cursory examination of the measurements of the length of head 

 shows at once that the dimension of the latter relatively to the size of the 

 fish is extremely variable. 



In the mature winter fish of 1884, which were measured, the length of 

 head varied from '127 in two herrings of 235 mm. and 265 mm. long 

 respectively, to "200 in a fish of 240 mm. long. In the spring months the 

 variation was "140 to '200. In the winter of 1885 the extent of variation 

 was from '137 in a fish 270 mm. long to '200 in a fish 220 mm. in length ; 

 and in the summer of 1885 it varied from '135 to -196. It will be seen 

 that the variation towards the larger extreme appears in all the seasons to 

 stop almost at the same point — the head does not exceed '2 of the length of 

 body (equivalent in the actual fish representing these conditions to about 

 •173 of the total length). Towards the other extreme, the extent of 

 variation is rather more unequal. In the immature fish examined, the 

 variation extended from '145 to "200, the herrings of all the seasons being 

 represented up to the extremes of these limits. It must, however, be 

 understood that these extremes of variation were only found in a very few 

 and therefore exceptional cases. The large proportion of the fish fell 

 within a much smaller though well-marked range of head variation. 



Including all the immature herrings of both winter and summer we find 

 that only 6 per cent, of them have the length of head of a greater propor- 

 tion to the body length than •156, and the majority — about 60 per cent. — 

 have the head length ranging between -166 and '180 of the body length. 

 The extent of variation among the mature herrings is all towards the side of 

 decreased length of head, the larger proportion having it between •I 51 

 and •I 65, and is rather more marked among the summer fish, among which 

 the larger fish have the relative size of their heads generally less than this. 

 Among the winter herrings, however, although the extent of variation is 

 equally great, the large fish seem to be more indiscriminately scattered 

 over the whole area of variation. It is undoubted that the immature 

 herring's head is relatively larger than that of the adult, and the increase 

 in relative size becomes emphasised the smaller the young fish may be. 

 There would appear also to be a tendency among the sexually mature fish 

 to increase in size of body rather quicker than in head length, this being 

 seen among the smaller, and presumably therefore, younger although ripe 

 fish. Table VI. gives the percentage of fish (in a total of 865) whose 

 head length fell within the various degrees of variation, marked at the 

 head of the columns in the table. 



The great proportion of these herrings have their heads of a relative 

 length of from '143 to -172 — indeed it might be said from '146 to '166 ; 

 and the table indicates that, as with the body length, all the extremes of 



