2 GO BULLETIN OF THE UNITED STATES FISH COMMISSION. 



ill both these apparatuses came from the same htitchiiig, and the con- 

 ditions of their existence were exactly the same. 



When the cover was removed from the first apparatus, the surviving 

 fish were found to be near the surface trying to got a breath of air. 

 The water had a soapy appearance and the characteristic odor of fish 

 in a state of decomposition. On the bodies of the dead fish, which had all 

 undergone the fatty metamorphosis, there was found a very luxuriant 

 cryptogamic vegetation of a whitish color. The surviving fish were 

 placed in another apparatus containing fresh water, and arrived in Brus- 

 sels in good condition on March 13, the water during the transportation 

 having a temperature of 5'^ C. [41^ F.]. As has been stated, the dead 

 fish rapidly underwent the fatty metamorphosis, and a species of whitish 

 mold developed on them, which gave to the water the appearance of a 

 solution of brown soaj), and a nauseating odor. The dead fish are very 

 obnoxious in the apparatus, as they produce germs which soon taint all 

 organisms. It is also important frequently to inspect the apparatus, 

 especially if the young fish have to stay in it any length of time. In 

 this case the water should be aerated, and renewed if possible, and all 

 dead fish should be carefully removed at once. 



It is also extremely dangerous to transport in one and the same ap- 

 paratus young fish of different age. Young salmonoids are extremely 

 voracious; when shut up in a narrow space, they will bite and endeavor 

 to devour each other, thus frequently inflicting wounds which are fatal. 



As has been shown in the transportation of young fish from Bavaria, 

 it is also important to use only very pure water, filtered if possible ; 

 the impurities of the water get into the gills of the young fish and choke 

 them. In the same transportation it was proved that the apparatus 

 should not be too high, for too great a column of water exercises an 

 abnormal pressure on the fish, which they are not able to bear. The 

 management of very large transporting cans is exceedingly difficult. 



We have noticed that the young of the Thymallus vexilUfer are the 

 most difficult to transport. When in a healthy condition they make 

 efforts to swim towards the surface of the water; if they remain at the 

 bottom it is a sure sign that they are sick. Salmon and trout, on the 

 contrary, keep quietly together at the bottom of the apparatus ; if they 

 become restless and rise to the surface to get a breath of air, it is a sign 

 that the oxygen in the water is diminished, or that the temperature is 

 too high. As the case may be, the water should be aerated or renewed 

 without delay, if it is possible to do this under good conditions. Care 

 should be taken, however, not to renew the water as long as the young 

 fish are in good health, for, as has been stated, any change of the ele- 

 ment in which they live will invariably cause them suffering. How- 

 ever, if the water has become vitiated by the presence of dead bodies, 

 one should not hesitate to renew it as soon as possible. 



We also made an experiment in transporting grown fish of the Cyprin- 

 idm family. We selected five Cyprinus awr«tMS,which were fully de- 



