of the Fishery Board for Scotland. 



383 



ments at loast show that the range of mutual fertility between widely 

 separated species is greater than has been generally supposed. 



Hybrids are also recorded as having been produced between the herring 

 and the pilchard, the turbot and the brill, the flounder and plaice, 

 between different species of carp, between the roach and the bream, 

 between the chub and the bleak, &c. In these cases, however, there is 

 little more than the record of the occurrence of hybrids. Among the 

 Salmonidse, more extensive evidence is found as to hybridisation, since the 

 members of this group have received special attention, and are now 

 largely reared artificially, and therefore under close observation. Even 

 here, however, the experiments made have generally not been extensive 

 or prolonged, and it is necessary for definite results that the influence of 

 intercrossing should be tested throughout several successive generations. 

 At the fish-culture establishment at Howietoun special attention has been 

 given for a number of years past to the intercrossing of various members 

 of the genus Salmo, and a brief description of some of these is given 

 below. Such experiments are of value, not merely in their relation 

 to many profound biological problems, but also in regard to the proba- 

 bility of promoting the inland fisheries by producing more vigorous and 

 valuable breeds. 



Hybrids between Lochleven Trout and Salmon. 



On the 27th December 1884, 7000 ova of an adult specimen 

 of Salmo saJar, taken from the Teith, were milted from a Lochleven trout. 

 On March 11, 1885, about 5000 of these hatched. There was 

 considerable mortality among them from the. time they were a month old, 

 continuing up to the time of feeding. On June 30, 1885, about 

 2000 were placed in pond 4. Nearly two years later about 1000 

 remained, one which was measured being 5 J inches in length. On March 

 1st, 787 were transferred to pond 7. At this time the largest was 

 between 7 and 8 inches long.- On May 22, 1889, they numbered in the 

 Botanical pond about 200, the larger specimens being about 12 inches in 

 length. 



On November 11, 1884, about 12,000 ova from a Lochleven trout 

 were milted from three young Howietoun (land-locked) grilse. In this 

 case above 2000 of the eggs escaped fertilisation, but the remainder 

 hatched out on January 28, 1885. A considerable number died subse- 

 quently. On June 19th, about 5000 of the hybrids were placed in pond 

 1. On July 26, 1886, 1260 of them were transferred to pond 8. On 

 October 12, one which was measured was 5 J inches long. On July 5, 

 1887, a specimen landed measured 10 inches. On May 22, 1889, there 

 were above 500 in pond 16, the larger measuring about 14 inches in length. 



Hybrids between Californian Trout (Salmo irideus) and Salmo fario. 



In April 1885, 3000 ova of the Californian trout were received at 

 Howietoun. They hatched out in May. In March 1889, the females 

 were ripe, and about 3000 of the ova were milted from & fario. 



Of the fry of S. irideus there is now about 30,000 (pure). 



It may be mentioned here that in March 1884 a number of eggs of the 

 land-locked Sabago Salmon from Maine, U.S., were received at Howie- 

 toun, and hatched in April. On the 22nd May 1889 they were in fairly 

 good health, with an average weight of about 2 lbs. 



