S9fi 



SCANDINAVIAN FISHES. 



The ventral iins are broader and ti-uncate, and their 

 average length is about 14Va — 13 % of tliat of the body. 

 The distance l)et\veen the latter tins and the tip of the 

 snout is on an average about 47 ?*, tiie preabdoniinal 

 length a})out 28 %, and the postabdoininal length about 

 "24 %, of the length of the body. 



The scales of the body we ]ia.\e already noticed. 

 i)\\\\ the liead and tlie tins are naked. The lateral line 

 runs from the teni])les along the postteraporal bone on 

 each side, descending at the top of the gill-opening, 

 but its backward coui'se on the sides of the body is 

 almost perfectly straight, \vith only a slight downward 

 curve at tiie extreme front. 



Tiie coloration is green, shading into steel-blue, on 

 the l)ack, silvery white on the sides, of a more or less 

 ]inre milk-wliite on tlu' belly. The back, as Avell as 

 the occiput and siwut, is slighth' transparent, l)Ut far 

 less tlian in the Smelt. The tip of the snout and the 

 point of the lower jaw are usually coloured with a black 

 pigment, which extends in a thinner coat to the ma.xil- 

 lai'ies and to the margin of the follicle of each scale 

 on the body. The gill-covers commoidy gleam with a 

 brassy lustre, especially at the top. Tlie adipose tin is 

 of the same colour as the back. The dorsal and caudal 

 tins are of a more or less dark gray, the other fins 

 light and transparent. The iris is silvery white, the 

 eyeball coal-black at the to]). 



The Vendace is really a Ikiltic tish. with the centre 

 of its range in tlie Baltic Sea and the lakes of the 

 countries — princi])allv the eastern ones — bordering on 

 the Baltic. But, if modern opinions as to the specitic 

 determination be correct, it also occurs in Scotland, to 

 whicli country, says tradition, it has been introduced 

 from abroad. The Irish lakes (Loughs Neagh, Erne, 

 Derg, and Corrib) contain a form, Coyegonus polhm, so 

 closely resembling the Vendace that the specific distinc- 

 tidiL between them can hardly be maintained. The Pol- 

 Ian as a, rule has fewer gill-rakers (/54 — S8 on the front 

 of the first branchial arch) and fewer anal rays (12 — 

 lo). At an earlier age than the other Vendaces the 

 Polian approaches in the depth of the snout the pro- 

 [Mirtions which we have alreadv remarked as most cha- 

 racteristic of the true (iw\niads". Tlie most distinctive 

 character of the Pollan, however, is the short l)ase of 

 the anal fin, which measures at most about ' ,. of the 



length of tiie body, and is so short that the least depth 

 of the tail is at least ' ., thereof. In this respect, as in 

 many others, the Pollan composes one extreme in the 

 form-series of the Vendaces (the alhiiJa group), the op- 

 posite extreme consisting of the Siberian Seldetkaii or 

 f'orcf/ot/Ks ^[erhli. Strangely enough, this difference in 

 foi'iu \\itliiu the Vendace group answers to the diffe- 

 rence we have above oliserved Ijetween the Salmons of 

 the Atlantic and Pacific basins. Tiie Onrovhjinrhus 

 grou[) i)f the Pacitic differs from the Saliini groiijj of 

 the Atlantic mainly in the greater length of its anal 

 tin; and the nearer the range of the aJhula group ap- 

 proaches to the Pacitic, the longer is the base of its anal 

 fin. We find the following average relations between 

 the length of the base of the anal fin and that of the 

 head reduced: 



These averages can hardly be the expression of a mere 

 accident, for they are attended with similar results in 

 several other relations; and there is thus a distinct 

 connexion here between the difference in form and the 

 geographical separation. Even in Sciuidinavia the true 

 aJbiila and the vimba show some geographical separation, 

 the former lieing commonest to the extreme north and 

 in Lake Wetter, tlie lattei- in the JUvlar valley and the 

 basin of Lake Wener; but our most tyjiical specimens 

 of rimha are from Finland. These two forms are be- 

 sides different, as we have seen above, in most of the 

 average proportions; but the changes of growth and the 

 se.xual distinctions reduce the differences to such an 

 extent that constant characters can hardly be adduced. 

 The \ endace occurs in all the provinces of Sweden, 

 except Gothland, Blekinge, Halland, and Bohuslaii''. 

 From Norway it was descrilied and figured even hy 

 AsCANius, Imt if is found only in Lake .Mjoseii .■md 

 some of the small lakes to the extreme south-east. In 

 Finland if is as common as in Sweden, up to about the 

 (iDfh degree of latitude. In the Arctic Ocean if is 

 wanting: l)uf from Western Russia and the Baltic Pro- 

 vinces its ran2:e extends over North firermanv to Hol- 



" SsnTT, Rtksinu.'^eets I'^nlmonider, y. '2?>?i. 



'' Cf. Underd. Bet. Ford. Ni/ Fi.^keri.^tadga 1883, p. 159. 



