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Part III. — Seventeenth Annual Report 



This s a very strongly marked series, thus the number of the vertebrae 

 is small (55 8 to 55-0). 



(b) Those of the northern North Sea, beginning with the spring- 

 herring of the Scottish coast and continuing in the coast- 

 herring of the Skagerrak (spring- herring of Bohuslan), through 

 the Sound to the spring-herring of Riigen, aud ending with 

 the spring-herring of the eastern Baltic. 



Its characteristics, in contrast with the foregoing, are — greater number 

 of vertebrae (and higher number of these to >e first haemal arch), a some- 

 what smaller number of keeled scales, 1 a longer head and tail 

 — i.e., they stand between the group (a) and the sea-herring. In the 

 west, on the Scottish coast, these herrings are very large in body, 

 with higher number of vertebrae (5 7*0), and are mostly winter- 

 spawners ; in the Skagerrak, somewhat smaller (V., 56 - 5), and spring- 

 spawners. Towards Riigen the variation continues in the same direction 

 (V., 56*0) as well as in the eastern Baltic (V., 55*5 to 50*0), and the 

 spawning-time reaches further into the summer. 



The races of the sea-herring of the northern North Sea and as far as 

 Gotland in the ."Baltic, and the races of northern coast-herring from Scot- 

 land towards the eastern Baltic, run in a very noteworthy fashion 

 geographically parallel. Especially astonishing is it that the connection 

 of the sea-herring of the eastern Baltic with those of the Kattegat through 

 the Belt and further through the western Baltic (autumn-herring of 

 Korsor) has corresponding to it the connection of the coast-herring of the 

 eastern Baltic with those of the northern North Sea through the Sound 

 by Riigen. 



The spring-herring of the Belt and western Baltic (Schley) form a 

 divergent group which, as already mentioned, find their nearest allies in 

 the southern parts of the North Sea (Zuyder See). 



To this characteristic parallelism in the location of the sea- and coast- 

 herring there is a corresponding parallelism in the body-characteristics. 

 Each one of the two groups always retains the same characteristic com- 

 position of the characters, and one can tell almost always the sea-herring 

 from the coast-herring; but for both groups we find in any one region 

 the same gradation or variation of the characters. The further the sea- 

 herring advances into the Baltic, so much the more do we find a decreas- 

 ing breadth of skull, decreasing number of vertebras and number of 

 keeled scales, as well as decreasing length of body, and it is quite the 

 same for the coast-herring. 



Having thus obtained some general notions with regard to the natural 

 grouping of the herring, we may now proceed to the particular races and 

 the details of their differences. 



Particular Paces of the Herring. 



I. Iceland Herring. — These herrings are of large size, mostly over 

 300mm. when in maturity ; number of vertebras large, in average over 57 ; 

 number of keeled scales behind ventral fin (k2) small, in average under 

 14 ; tail tolerably long ; head thick-set, short, high, and broad, with very 

 short snout ; eyes very large, and operculum very broad ; length to breadth 

 index of the skull large, in average 31 — brachycephalism. 



Time of spawning not yet definitely known — probably in spring or 

 summer. 



IJ. Spring Herring of Norway (Vaarsild). — Very large in size, in 

 maturity over 300mm. ; number of vertebrae very large, in average over 



