of the Fishery Board for Scot haul. 



313 



How the opposite extremes of variation are found in herrings of the 

 same shoal — an argument against there being any permanent or well- 

 defined racial distinction among them — is shown by the position of the 

 dorsal fin on the above examples (Table XXVIII.) from various places, 

 and at different seasons. Each comparison — and only a few are adduced 

 — is made between herrings from the same catch. 



All the variations given in the above tables are deduced from the 

 length of the body only as a standard of measurement, and the total 

 length of the herring in its variations being made up of the three main 

 divisions of head, body, and tail (caudal fin), the body is chosen as the 

 standard, being the main portion of this length. It is, therefore, assumed 

 to be invariable, at least we cannot prove it is not so except by comparison 

 with some other standard which in its turn would appear as invariable — 

 and the head and caudal fin lengths are excluded from this standard so 

 that variations in total length are referred to them, and the examination 

 of the variations in other characters is not affected thereby. In one way, 

 however, a variation in the length of body itself might be thought to be 

 correlated with variation in its segmentation, and that therefore an 

 increased number of vertebrae implied an increased length of vertebral 

 column. The examination of this feature in about an equal number of 

 our east and west coast herrings shows no distinction between them either 

 in respect to locality or season, the percentages being nearly similar. As 

 the vertebrae form round the upturned terminal portion of the notochord,* 

 remaining more or less — often very slightly — visible in the adult, it is 

 necessary to explain that in these numbers are included the first two 

 shorter vertebrae, the remainder of the body vertebrae and the caudal 

 vertebrae, including as the last that which has its anterior end of the 

 normal disc-like form for articulation with the preceding vertebrae, but 

 has its posterior end much contracted, bent upwards, and bearing the so- 

 called urostyle. The succeeding vertebrae — clearly defined and separable 

 in the very young but partly coalesced and aborted in the adult — being 

 discarded from the enumeration. I believe the last vertebra as here 

 adopted has also been often omitted in the enumeration of the herrings 

 vertebrae. Counted in this way it is found that the vertebrae in both the 

 east and west coast herrings number from 55 to 59. Only 1 per cent, 

 was found to have only 55 vertebrae, and only a single example was got 

 with so many as 59 ; this number may, therefore, be considered as a very 

 abnormal condition. With 58 vertebra? there were counted 8 per cent., 

 and the remainder had 56 or 57, over 35 per cent, having the former, 

 over 55 per cent, the latter number. In all the cases examined the total 

 length of the vertebral column was carefully measured, the result showing 

 conclusively that its total length was unaffected by the number of verte- 

 brae. A tabulation of these results, as found on herrings of various lengths, 

 would simply show 56 to 58 vertebrae, as occurring in every grade of 10 

 mm. length of vertebral column from 125 mm. upwards. 



The conclusion at which I arrive from these observations is that there 

 is no true racial difference between the herrings of the various localities 

 around our coasts ; and while the investigation, as mentioned in Part I. 

 of this paper, points towards a distinction between the herrings frequent- 

 ing our shores in summer and in winter, it is so small, not only in its 

 actual extent, and more especially in the circumstance that there is no 

 sharp line of distinction between the two, but that many of the summer 

 herrings are found to be marked by the same characteristics as those of 

 winter, — that I don't feel justified from the investigation in considering 



* "The Skeleton of the Herring," Fifth Annual Report of the Fishery Board for 

 Scotland, 1887. 



