THE SALMON, THE TROUT, AND THE SHAD. 741 



says that the female Las jnst as strongly curved a hook, it must be 

 considered an error. Why this peculiarity occurs only in the one sex 

 and not in the other has not yet been explained. It has been said that 

 too long a sojourn in fresh water, and swimming against the stream, 

 had caused it j but there is no reason why the hook should not develop 

 itself just as much in the female as in the male. 



This hook occurs likewise in the lower jaw of the males of other spe- 

 cies of salmonoids. Thus, Wartmann 1 has found it in Trulta lacustris 

 (Siebold) ; Meckel, 2 in Trulta fario (Siebold) ) he also thinks that this 

 peculiarity is found in most of the species of the salmonoids. 



On the strength of these facts, I must presume that of the salmonoids 

 belonging to the ocean only two species occur in the Rhine : 1. The 

 " Lachsforelle," (sea-trout,) Fario argenteus Yal. ; Trutta trutta ac- 

 cording to Siebold ; 2. The " Salm," (salmon,) Salmo salar Lin.; Trutta 

 salar according to Siebold. I cannot in this place refrain from making 

 the remark that people have been induced to accept the two species, 

 Salmo salar and Salmo hamatus, only by the occurrence together of 

 fruitful and temporarily barren specimens of one and the same species 

 of Salmo salar. 



Henceforth, I shall exclusively use SieboWs nomenclature, as by his 

 investigations the position of our salmonoids in the general system has 

 been definitely settled. 



I now turn to the investigation of the food of Trutta trutta and Trutta 

 salar in fresh water — the Rhine. 



The question, What is the food of our salmonoids in fresh water and 

 in the ocean, is not only of scientific but also of great economical 

 interest. It is, however, very strange that the ichthyological works 

 contain scarcely any or wrong data regarding this point. 



Valenciennes speaks only in one place of the food of Trutta salar : 3 

 "La nourriture consisteen poissons etl'ou dit qu'il pr6fere l'ammodite — 

 Ammodytes tobianus. m As the fish in question (Sard-launce) lives in the 

 North Sea and in the Baltic, this fact would refer to the food of the fish 

 while in the ocean ; but nothing is said regarding its food in fresh water. 



Figuier, on the other hand, says : 5 " On n'a pu faire jusqu'ici que des 

 conjectures sur leur genre d'alimentation dans la mer, raais on est plus 

 instruit de leur maniere de vivre dans les eaux douces (?). Pendant leur 

 premier age, ils vivent d'insectes, de frai, et aussi de petits poissons, 

 des qu'ils ont atteint une certaine taille. A l'etat de grilse et a l'etat 



1 Wartmann, Von den Rheinanken oder Illanken, in ''Scbriften der Berlinischen 

 Gesellschaft natnrforsckender Freunde," vol. iv, 1783, p. 55. (Quoted from Siebold, 

 op. cit., p. 32.) 



2 HccJcel, Bericht einer iclithyologischen Reise, in the " Sitznngsberickte der kaiserl. 

 Akademie der Wissenchaften," vol. viii, 1852, p. 355. 



3 Valenciennes, op. cit., p. 197. 



4 Its food consists of fish, and it is said that it prefers the SnrdAimnce-Ammodytcs to- 

 bianus. 



5 Figuier, La vie et les mcenrs des animaux, Paris, 18G8, p. 106. 



