578 REPOET OF COMMISSIONER OF FISH AND FISHERIES. 



been sponged with water ; then the milt is squeezed over them, and, 

 finally, a small quantity of water is added, while the basin is tilted to 

 and fro. If the egg be kept thus dry, the micropyle will remain open 

 for seveial hours ; but in water, the egg immediately begins to swell 

 and the micropyle closes, shutting out the spermatozoa.* 



As soon as the hatched fry had absorbed their yolk-sacs, they were 

 turned loose in the brook, where they grew during the parr stage, feed- 

 ing in the brook itself, or in the shallows of the upper pond. Taking 

 on the smolt coat, they descended toward the lower end, seeking the 

 salt-water, when, as ill luck would have it, they found a small hole, 

 and the greater part escaped, some of them returning next spring to 

 the foot of the dam. Enough, however, remained to show that the 

 smolt will continue his growth when confined in a salt-water pond. 

 Trout, which were raised beside the salmon, were more quiet and did 

 not escape. They throve amazingly and grew to a great size. 



The owner of an artificial brackish pond may either depend on the 

 natural increase of the fish that were before in the brook, or he may 

 add fresh material. If he depends on natural breeding, he will place 

 adult fish in the brook where they will breed. Or he may have a hatch- 

 ing-house, which could be placed near the brook, and in which young 

 fry could be raised to be set free in the shallowest portions of the 

 water. 



In a pond and brook of good extent, several species would doubtless 

 do well, living side by side. Such species and varieties as the true sal- 

 mon, the land-locked salmon, sea variety of the brook-trout, the Sebago 

 salmon, and the forkep-tailed salmon-trout of the great lakes migh:^ 

 profitably be cultivated. In addition to these. Professor Rasch recom 

 mends hybrids, which are never fertile, and which are therefore fat and 

 in good condition during the breeding-season. Mr. Hanson, of Stavan- 

 ger, on the west coast of Norway, has observed that a hybrid from the 

 brook- trout {Salmo fario) and the charr (*S'. unibla) grows much faster 

 than either of these species, because none of the flesh and fat produc- 

 ing materials are expended in developing the large organs of reproduc- 

 tion. Taking our brook-trout as one, the breeder might select the 

 other fish from such as were at his command. Doubtless some near 

 species, such as the togue of the Maine lakes, or the forked-tailed sal- 

 mon-trout of the great lakes, would yield the surest imj)regnatiou. 



D— DESCRIPTIONS OF IMPROVED APPARATUS IN FISH- 

 HATCHING. 



1. — SHAD-HATCHING OR FLOATING BOXES. 



Seth Greeii's box. — The devices used in shad-hatching are, first and 



* The dry method of impregnation has since been successfully tried by Mr. Atkins 

 in breeding salmon. 



