1060 REPORT—1885. 
be fertilised by the milt of the males diffused in the surrounding water, it is not 
difficult to believe that this fluid from the male of one genus might come into 
contact with the eggs from fish of another species, genus, or even family, and a 
hybrid offspring be thus occasioned. But the size of the micropyle of the ovum 
and that of the spermatozooid of the milt must be of conforming capacities or 
fertilisation would be a physical impossibility. 
Fraisse alludes to a hybrid offspring between a brook-trout and a burbolt, or 
between fishes belonging to two distinct families; and in the ‘ Bulletin of the 
United States Fish Commission’ in 1882 is an account of a hybrid between a fish 
pertaining to the herring family, Clwpeide, and the striped bass, Roccus lineatus, a 
percoid which supplied the milt. 
Livingston Stone observed in 1869 that he had crossed the yellow perch, Perca 
flavescens, with the glass-eyed perch, Zucioperca, when the embryos continued to 
develop until the seventh day, and then ceased to do so. Crosses have also been 
effected between the golden tench, Tinca vulgaris, and the common carp, Cyprinus 
carpio ; the rudd, Leuciseus erythrophthalmus, and the gold carp, Carrassius auratus ; 
the roach, Leuciscus rutilus, and the bream, Adramis brama; between the rudd and 
the bream ; the chub, Leuczscus cephalus, and the bleak, Alburnus lucidus, &e. 
Restricting ourselves to the recorded instances respecting hybridisation among 
the Salmonide in Great Britain, we find it observed upon by Willughby in 1686, 
when it was remarked that he was persuaded that the salmon and the various 
forms of trout interbreed; and many authors in this country have erroneously 
asserted that par were hybrids, until this question was set at rest by the fish 
culturists. Mr. Shaw, in-1841, observed that his ‘experiments with the ova of the 
common trout and salmon had been quite successful;’ that ‘those produced 
between the salmon and the salmon-trout appeared to partake more of the external 
markings, silvery coating, and elegance of form of the par than any of the others. 
Those produced between the salmon and the common trout, and between the 
common trout and the salmon-trout, had in every respect more the appearance of 
the common trout than the former.’ 
The Ashworths, in 1853, remarked upon rearing offspring from the ova of 
trout fecundated by salmon milt. Davy, in 1858, also observed that Mr. Reynolds 
mixed together the roe of the lake-trout and the fluid milt of the char, and 
in seventy days young fish were hatched. 
The ponds at Howietoun, where the breeding of the Salmonide are carried on, 
are thirty-two in number, constructed in accordance with whether they are 
intended to accommodate breeders or for rearing purposes; the whole being sur- 
rounded by a strong paling five feet high, with an iron spike six inches in length 
surmounting each post. 
The first question which seemed to require being settled was whether, if salmon 
were crossed by trout, a sterile or a fertile race of hybrids would result? If they 
were sterile, would they or would they not possess anadromous instincts? It 1s 
evident that, could a breed of fish be procured that would not migrate seawards, 
such would prove most valuable in the upper waters of rivers, as the Thames, 
which is so polluted in its lower reaches as to be practically impassable to the finny 
races, and consequently cannot be frequented by anadromous forms. 
Leuchart refers to salmon ova, in 1878, having been fertilised by trout milt- 
No mention is made of the progeny attempting to spring out of the pond in which 
they were confined, while ova and milt were procured from these hybrids when 
twenty-two months of age. 
At Howietoun some salmon eggs were hatched in March 1881, and on Novem- 
ber 29, 1883, or at thirty-two months of age, milt was procured from these fish ; but 
it was not until November 7, 1884, or when forty-four months old, that ripe eggs 
were furnished by any of these fishes. It would thus appear that the period at 
which the pure salmon breeds is at least a season later than the trout when kept 
under the same conditions. 
December 24, 1881, about 20,000 Lochleven trout ova were fertilised at 
Howietoun with salmon milt, and these hatched on March 9, 1882. From time to 
time some of these hybrids were examined, but none showed signs of breeding until 
