742 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



adulte ils devorent une foule de poisson (?).' n Block 2 says that the salmon 

 lives 011 small fish, aquatic insects, and worms, and that it could be 

 enticed by dragon-flies, worms, and small fish if these were attached to 

 the hook (?). 



In Heckel and Kner's work, 3 1 find, regarding the food of Truita trutta, 

 only the very general remark that "it is a powerful fish of prey." SieboWs 

 excellent work 4 contains several observations regarding the food of our 

 salmonoids while in fresh water. 5 The most important, and, as will be 

 seen afterward, the most correct, (p. 246,) is the following : " I cannot 

 in this place pass over in silence the fact that in observing and describ- 

 ing the digestive organs of the salmonoids, no attention whatever has 

 been paid to the circumstance that these fishes do not eat anything before 

 and during their spawning-season, but are merely intent upon spawning, 

 during which process their empty stomach is unusually contracted ; the 

 ' appendices pyloricce 1 and the gut itself being filled only with the differ- 

 ent secretions of the digestive organs.-' From the following, it will be 

 seen whether and in how far the remarks of the above-quoted ichthyolo- 

 gists are correct. 



On the 20th September, 1873, I examined the stomachs of the first 

 two specimens of Trutta salar, which had been caught in the Ehine, in the 

 neighborhood of Bonn. They were female spawn-salmon ("Laichsalme") ; 

 {. e., salmon which had ascended the Ehine for the purpose of spawning. 

 The eggs of both these specimens were of the size of a pea, and ripe 

 for impregnation. The sides of the stomach were strongly contracted, 

 and the pyloric cceca were exposed ; i. e., they were not covered with 

 masses of fat, as is the case with other specimens — as I shall detail 

 later — of the same species. The section of the whole digestive organs 

 showed the following : The oesophagus and the stomach itself contained 

 nothing but the secretion of the mucous membrane, a white and mostly 

 very sticky mucus, which is always there, whether there is food in the 

 stomach or not. At the place where the stomach proper joins the in- 

 testiue, and where the "appendices pyloricce" commence, this mucus 

 increased in quantity, and at the same time assumed a yellowish-green 



1 So far, we have only been able to to make conjectures regarding their food while in 

 the ocean, but we are better informed regarding the mode of living while in fresh 

 water (?). When quite young, they feed on insects, spawn, and small fish, until they 

 have attained to a certain size. In their third year and when fully grown, they devour 

 great quantities offish (?). 



2 Block, Oekonomische Naturgeschichte der Fische, Berlin, 1732, pp. 133 and 137. 



3 Heckel and Kner, op. cit., p. 266. 



4 Siebold, op. cit., pp. 246, 276, 299, &c. 



6 After I had completed this treatise, there appeared in the "Acta Universitatis Lun- 

 deusis," Lund, 1871-72, a work by P. OUson— Jakttagelser ofver skandinaviska Fiskar 

 Foda— in which I find very valuable information regarding the food of Truita salar and 

 Trutta trutta while in the ocean. I shall again refer to this work, as thi3 information 

 has enabled me to yive fuller details in one place. 



