1884.] HYBRIDS AMONG THE SALMONID.E. 583 



were opened, and the ovaries were found quite distended with eggs, 1 

 almost ripe, but still just adherent. On looking at these fish in the 

 water, some were seen to have black spots over the bank as well as 

 on the sides, but others had not. For the last three weeks these fish 

 have been fed on young Lochleven Trout. 



That Salmon may be reared in ponds, and in due time, if males, 

 give milt, has been universally admitted, but many have denied that 

 females can produce ova without first descending to the sea. Grilse 

 are well known to breed earlier in the cold season than do mature 

 Salmon ; this it has been surmised must be owing to their being fish 

 in which the time for propagating their species has been deferred for 

 a season, or from February or March until the commencement of 

 the following winter in October or November. Experiments at 

 Howietoun have shown that from Salmon-eggs hatched in March 

 1881 most of the male parr had milt in November 1883 ; while two 

 or three smolts which jumped out of the pond, and so met their 

 deaths, had ova which in suitable places 2 would have matured that 

 year. In 1884 all the females it appears would be ready to breed, 

 but did they do so in rivers and had to depend on male Salmon for 

 fecundating their ova, universal sterility would ensue, as the latter 

 fish breed later on in the winter season. The parr of Salmon are 

 not then normally ready for impregnating the ova of mature Salmon, 

 or "to mingle with the river-trout" as Ur. Giinther suggests, but 

 are available to fertilize the ova of the grilse. 



We may well ask the question whether it is a physiological 

 necessity, as asserted by Rasch, for female smolts to descend to the 

 salt water before grilse can develop eggs? This theory is held by 

 some, and appears to be rather widely accepted. I have not con- 

 sidered it worth while to describe the grilse at Howietoun reared 

 from Salmon -eggs, but have kept specimens for reference ; conse- 

 quently I am in a position to maintain that from the eggs of the 

 Salmon, parr, smolts, and grilse with eggs have been reared in the 

 Howietoun pond. 



Of course the views I have held and still hold, that Salmon are 

 marine forms which, in accordance with their anadromous instincts, 

 come into our fresh waters to breed, as does the Shad, may or may 

 not be correct. The reasons which have induced me to adopt these 

 views I do not propose discussing in this paper ; but I would point 

 out that as the descent to the sea is not indispensable to the deve- 

 lopment of eggs, it therefore cannot be a physiological necessity, and 

 perhaps we may class it among many other instances as "inherited 

 instinct." 



I have formerly shown that the milt of a young parr (hatched 

 1881 and milted in 1883) has insufficient vitality to properly fertilize 



1 I received the following telegram yesterday, Dec. 1st, 1SS4, from Howie- 

 toun : — "Two of the grilse spawned to-day, en a perfect; kept one female as 

 evidence.'' This alludes to one being placed in spirit for future examination 

 by anybody who may be dubious. 



2 Perhaps if these fish are kept another year in earth-ponds with a gravel 

 water-course leading to them, more success will be obtained. 



