258 SALMONID^ OF BRITAIN. 



amount of ruuning water to carry enough air in solution to equal the requirements 

 of the fish. Temperature alone can hardly be the reason, because that of the 

 water in the Howietoun ponds on the same day was 66° ; but there the supply, 

 coming down the burn from Loch Coulter, was ample. The foregoing, however, 

 proved one fact, that fertile female fish may be raised by hybridizing the eggs 

 of trout with the milt of salmon par: that females so raised may breed in 

 their third or fourth season, similarly to salmon, but later than in the generality 

 of trout. 



One of the fish that survived was a male, employed Nov. 6th, 1886, to fertilize 

 3000 Lochleven trout eggs : on January 25th, 1887, about 80 hatched, and on June 

 27th the lot, numbering 55, were put into pond no. 2 at Howietoun; they were 

 strong, and from 1^ to If inches in length. 



The other, also a male, was likewise employed on Dec. 5th, 1886, for this 

 l^urpose, to fertilize 7000 eggs of a Lochleven trout, but on Feb. 27th, 1887, only 

 one or two hatched. But these instances proved that this class of hybrids may be 

 fertile.* 



Hybrids between Lochleven trout and Salmon. 



December 27th, 1884. — Seven thousand ova from a Teith salmon were milted 

 from a Lochleven trout, and about 5000 hatched in the old house on March 11th, 

 or after incubating 75 days. There was a great mortality from when they had 

 attained to a month old and continuing up to the time of feeding, many being 

 weak and dropsical. June 30th, 1885, about 2000 were transferred to pond 4 ; 

 Feb. 22nd, 1887, about 1000 remain, and they look very well, they have 13 par 

 bands, a white edge to dorsal and anal fins, and a slight one to the ventral. Not 

 many red spots. One measured 5| inches long. March 1st, 787 were shifted to 

 pond no. 7, the largest being from seven to eight inches long, but several were 

 merely from two to three inches in length. 



Hybrids between Salmon smolts and Lochleven trout.t 



Day, Froc. Zool. Sue. 1885, p. 242. 



November 11th, 1884. — About 12,000 eggs of the Lochleven trout, having an 

 average diameter of 0-21 inches, were milted from three male Howietoun-bred 

 smolts, the largest of which was twelve inches long and the shortest ten inches, 

 all being silvery, but showing the remains of par bands. The following were 

 the number of eggs picked out as dead : — November 34, December 28, January 

 25, while 2295 were found to have escaped impregnation. The rest hatched 

 January 28th, 1885, or in 78 days, but between then and February 25th about 

 1000 died, for although the alevins looked well for the first three weeks (except 

 that their eyes were rather small), a large percentage then showed signs of 

 deficient vitality, the yelk-sac did not absorb, the young fish became dropsical, 

 and nearly 2000 died. On June 19th about 5000 were transferred to pond no. 1 

 at Howietoun, along with some similar hybrids. In all these fish the adipose 

 dorsal fin was lead-coloured. On July 26th, 1886, 1260 fish were shifted from 

 no. 1 to no. 8 pond, and on October 12th one which was measured was Sj inches 

 in length. July 5th, 1887, another, taken with a landing net, measm-ed ten 

 inches. 



* At p. 103 I have already recorded how 100 eggs from a dead or dying grilse were milted 

 Nov. 7tb, 188-1, from a male Lochleven trout, and eighteen hatched January 23rd, 18S5, or in 77 

 days; seven remained July 4th, 1885, and were put with hybrids of the same description into pond 

 no. 4. 



t On the same day about 800 eggs of Lochleven trout were milted from three Howietoun 

 raised pars and smolts. A fair number hatched on February Stli, or in 90 days, but subsequently 

 many succumbed to dropsy. June 19th, 1885, about 400 were shifted to pond no. 1 at Howietoun, 

 along with some other similar crosses. 



