CROSS-BREEDING OF FISH. 79 



the combination made consequently remains un- 

 known. 



In the year 1877, I made some experiments in 

 crossing the native brook trout with the California 

 salmon, the spawn of the latter having been sent 

 from the Pacific coast, and the fish hatched and 

 reared at the Caledonia hatchery. The result of 

 this experiment was that the fish were nearly all 

 deformed in some way. We kept some of them until 

 they were eight or nine years old. They showed 

 characteristics of both parents, but resembled the 

 salmon rather more in general appearance than the 

 other parent. When they were between three and 

 four years old they began to show indications of 

 spawning. One of the peculiarities discovered was 

 that male fish were either absent or sterile. On at- 

 tempting to take the spawn from the females artifi- 

 cially, an unexpected difficulty was encountered. 

 To all appearances they had the organs of the 

 brook trout and the eggs of salmon, which are much 

 larger than those of the brook or speckled trout 

 By the careful use of a knife we took the spawn from 

 the fish, gently pressing the forefinger down the 

 fish's abdomen. There being no milters, we tried to 

 fertilize the eggs thus taken, by using a male brook 

 trout, but without success, as none of the fertilized 

 eggs ever produced fish. The original fish grew 

 well, and when about three and a half years old 

 some of them weighed nearly if not quite two 

 pounds. The cross never amounted to anything 

 practically, but had much interest as an experiment. 

 The salmon used had been hatched and reared en- 

 tirely in fresh water, and were consequently not in 



