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Appendices to Fifth Annual Report 



presumably, therefore, of the age of the herring, and is not an indication 

 merely of variety. 



To express this the more clearly, the extent of variation is divided in 

 the following table into eight divisions. 



In Part I. I suggested that, so far as the inquiry had gone, it seemed to 

 give evidence of there being some racial distinction between the herrings 

 of summer and winter. We may examine this in light of the above table. 

 We see there that the head does not increase in size at the same rate as 

 the body of the herring, and if we consider the percentage to the total of 

 each size received, it is found that winter fish were larger as a whole than 

 those procured in summer. Of the winter fish referred to, 42 per cent, 

 were over 210 mm. in body length, while in summer only 14 per cent, 

 were so. Now, if the various columns of head ratios for each division of 

 fish length in winter are compared with those of summer, it will be per- 

 ceived that, although both the summer and winter fish agree pretty closely 

 in the relative size of their heads, yet there is a tendency among the winter 

 fish towards the possession of a proportionally longer head than belongs to 

 the summer herrings. It has been previously stated, as a result of the 

 examination of this feature in the fish en masse, that the percentage with 

 the larger size of head was greatest among the winter herrings, and the 

 table (XXIV.), which sufficiently shows this for all lengths of fish, con- 

 firms the statement. As the percentage of the smaller fish was greater in 

 summer than winter, the distinction was partially obscured. 



While such a small difference alone as occurs between the head length 

 of the winter and summer fish does not warrant us in concluding it to be 

 a good racial distinction, yet the fact brought out by the tables, that the 

 difference applies to nearly all the gradations of size, makes it worthy of 

 consideration as such, if other evidences can be brought forward. A similar 

 table of the head length in the smaller and immature fish bears out the 

 statement that the increase in length of head is not equal to that of the 

 body length. I refrain from appending it, as it fails in giving a fair com- 

 parison between these fish in summer and winter, because a sufficient 

 number of examples was not collected, only such being examined as were 

 casually procured, while many of those in winter being got in sprat nets 

 were too small for comparison with the larger winter immature fish. 



The most evident difference, small although it may be thought, between 

 the summer and winter herring has been stated to occur in the position of 

 the dorsal fin. Table XXV. shows the frequency of the various dorsal 

 fin-centre positions on the mature herrings of every 20 mm. difference in 

 body length. 



From the table it appears that there is a very slight gradation back- 

 wards in the position of the fin from the smaller to the larger fish. But 

 the most important point to notice is that in herrings of all the lengths 

 the common position of the dorsal fin centre is a stage further back on the 

 summer than on the winter herrings. It will be seen, too, that the whole 

 ground of variation is wider among the winter than among the summer 

 herrings. Of course it might be expected, from the evidence given above, 

 that the position in the summer fish would not have an extreme range of 

 variation anterior to the normal position so great as would the winter 

 herrings. But for the same reason it would be expected to exceed the 

 variation on the winter fish in backward extent. It does not, however, 

 and in fact, of all the fish examined, a slightly larger percentage of the 

 winter fish fell into the last division — with fin centre from - 533 to *545 

 of the body length — than of those of the summer season. This, of course, 

 detracts somewhat from the value of the suggestion that the position of 



