830 



SCANDINAVIAN 1-ISIIES. 



SnliiiDU (0)i<(irli. fschairi/fsritd). lins Ijecii iiiti'ci(liicL'(l 

 \\itli sufce.s.s ll^• jjiscieultural iiietliods not ()iil\- iiitu tlie 

 iLastern States of North America, but also into Australia 

 and Europe, though not yet, to the best of our knowledge, 

 into Scandinax ia. The Scandinavian fauna has, how- 

 ever, l)een enriclied in very recent \'ears, according to 

 a iicxvspaper paragraph at the beginning of 1892, })y 

 the introduction from Germany of a form planted in 

 the latt(!r countrv, the Californian Rainbow Salmon 

 {SaliiKi /r/th'iis). Tlie said form, together with a (_'harr 

 form — or ivitlicr an intermediate form between the 

 Salmon and Chai'r — has its original home west of the 

 Ivockv Mountains and in the Pacific Ocean, although 

 they both belong to the course of develoi)ment other- 

 wise represented only to the east of this mountain 

 range. A closer examination of these forms leads us, 

 however, to the result" that in them we have a blending 

 of characters most naturally to be explained, if not on 

 the assumption of tndjridism, as a reminiscence of the 

 time when the Salmon and ('liai'r, in their common de- 

 \elopment, \vere not fully differentiated from each other. 

 Another American form, a Charr from the Eastern 

 .States {Salmn foi/fiiialis), has been cultivated Avith suc- 

 cess in England, Wales, and Scotland. Salmo fouthialh 

 is also an intermediate form between the Salmon and tlic 

 Charr, the oidy character — though not of great vali- 

 dity — in which it differs from the Greeidand Charr, 

 the absence of teeth on the l)asibraiichial bones (ir\oid 

 teeth), being a character of the Salmon''. The lirook- 

 Trout {S. fontinalis) has been crossed both here and 

 in America xvith the Salmon as well as xvith Euro|iean 

 Charr; and these experiments have tanglit us, among 

 other things, that tlie charai-tcr which otherwise com- 

 poses a constant distinction between Salmon and Charr, 

 the feeble ossification and toothlessness of the vomer in 

 the latter, loses its validity in these livl)rids'. Conse- 

 quently, in elucidating the relations of the forms to each 

 other, here as in the ])receding family, we have to 

 reckon with hybridism as an important factor in the 

 modifications of the types. To all appearances the ge- 

 nus has its original home in the American seas, wiiere 

 Salmon and Charr still occur in masses almost incon- 

 ceivable to the European. 



From tlie preceding family we have li-ai'iit tliat 

 cross-l)ree(ling ma\' take place not only between differ- 

 ent species, but also between different genera. Hybri- 

 dism alone cannot, therefore, prevent the distinguishing 

 of the species. lUit tiie variabi]it\- of form \vithin the 

 genus S(iI))>o has liitherto I'endcred it impossible to de- 

 fine with certainty the luimerous sjiecies that have been 

 adopted; and we doubt wliether the observer who con- 

 sistently requires trustworth\- and distinct characters can 

 recognise more than three luiropean species of the ge- 

 nus: the Salmon, the Huch, and the Ciiarr. As yet, 

 however, to the Ijest of our kiKjwJedge, onh' Nilssox 

 and SuNDEVALL — the latter in the titles of the figures 

 in PI. 58 and 59 in the former edition of "Scandinavian 

 Fishes" — have ventured to advance this simple ojiinion. 

 Still, both from a scientific and an economical point 

 of \iew, it is of importance to know the conditions that 

 involve the said inconstancy; and to this end it has 

 Ijeen necessarA' to denote by special names the moi'e 

 or less constant forms that appear under different cir- 

 cumstances and in different localities. As regards the 

 Salmon, general credence has been given in recent times 

 to the opinion first advanced by Lilljebokg and after- 

 wards by Wii>F,(;r,EX, namel'S" that we can distinguish 

 between txvo "species", The Trout'' (Sdhi/n fnifta, Sw. 

 ffrdhi.reii) and the Sahnon' (iS'. salar, Sw. Iilditkhi.reii). 

 The same ajijilies in essential points to tlie Scandinavian 

 Charr, among which we can generally distinguish with 

 ease Uvo forms, the Northern Charr {Sdlnio alpinus, Sw. 

 Lap2)Jands-r6clingen) and the Sa^Uiling (.S'. Hah-eVtnus, 

 Sw. Yettcnis-rod'nHje)!). ( )f the Fluch, which, at least 

 U]) to the present, cannot be claimed for the Scandina- 

 vian fiuna, there are also two forms, the Siberian Ilncli 

 (Salmo j!Hriatili.s) and the Danube Huch {S. Imclio). 



The Scandinavian forms of the genus Salmo max 

 in general lie distinguished most readih' in the fallow- 

 ing manner: 



A: Xumbcr of scales in a longitudiual row 

 above the anal (in, for an extent of ' ,„ 

 of the length of the body, at least 23 

 (23—30). Salmo iimbla. 

 a; Distance between the ventral iins and 



the tip of tbe snout more tlian lialf 



the length of tbe body Salmo ^alcelums. 



" Smitt, Bikstmiseets Salmoiiider, Vc-t.-AUnd. Handl., Bd. 21, No. 8, ]>. 14;!. 

 '' Cf., however, Smitt, 1. c, t:d). mctr. V and VI, Nos. 371, 38C and 4.'i8. 

 ' Cf. Day, Britisli and Irish .Sahnoniihr. p|.. '201 and 270, ng. 52, 2 ,ind 2a 

 " D.\y, British and Irinh Salmonida; )i. 14:!. 

 ' D.«-, ibid., p. 51. 



