BULLETIN OF THE UNITED STATES FISH COMMISSION. 281 



supi>lied by running water, and tlieir food has been continued with 

 minced horse-flesh. The .young of Salmo namaycusli and 8. fontmalis 

 have succeeded well and have attained a length of from 10 to 12 centi- 

 meters ; but the landlocked salmon have not given the same result. All 

 these fry were kept during the winter in the lower trenches of the 

 hatching shop, and in the spring are to be distributed in the outside 

 basins and preserved at the establishment. Last autumn we noticed 

 that the males were full of milt, but that the females had no eggs ; be- 

 sides many females have died. There are still sixty of these fry which 

 weigh fron\ 250 to 300 grams [about S| to 10| ounces avoirdupois], and 

 we will try to keep them for reproduction, if possible. 



" In 1882 we distributed some fry from little Fera of the Lake of 

 Constance, in the fish-pond of Bouzey, and we had this winter the satis- 

 faction of catching specimens from 18 to 22 centimeters in length. 



" I avail myself of this letter to ask the Society to send us, if it is 

 possible, some eggs of Salmo qiiinnat, S. namaycusli, and S. fontinalis, in 

 order to distribute the fry in the fish-pond of Bouzey and in the reser- 

 vations of the jMoselle, while preserving a few of each species at the 

 establishment." [Bulletin, March, 1884, p. 397.] 



Salmon. — Mr. Bartet, chief engineer of bridges and roads, gave the 

 following account ofresultsobtainedfrom eggs of the diiferent species of 

 salmon which were distributed by the Society and placed for hatching in 

 the aquarium of Trocadero : 



" Sixty per cent of the eggs were successfully hatched. The food 

 which was givea the fry at the beginning was mud-worms chopped fine 

 and afterwards whitefish, also chopped fine. Their growth has not 

 been rapid ; and the youngfish are yet in the inclosed water, and have 

 not been set free in the river. During the first four months after the 

 hatching we lost many of these fish, and now only a tenth part remains. 

 Befoie placing them in one of the aquarium troughs and taking thera 

 out of the hatching apparatus, we kept them, for about two months, in 

 an intermediate basin 5 decimeters in depth, with a bottom of pebbles. 

 The less mortality was j^roduced in the hatching apparatus. 



"That apparatus consists of eight troughs i^lacedin a row one above 

 the other, each trough being 50 centimeters long by 20 centimeters 

 wide and 15 centimeters deep, whose inner walls are sheets of glass her- 

 metically sealed. It is supplied by water from the Vanue, which is j)re- 

 viously filtered through a sponge contained in a terra-cotta pot, from 

 which the discharge is about 150 liters an hour. The eggs were placed 

 on screens formed of a framework of wood and a rod of glass. 



" The hatching is conducted normally ; that is to say, it takes ijlace in 

 about six weeks after impregnation, and the reabsorption of the umbili- 

 cal sac occupies the same time. The temperature of the water is kept 

 at between 9 and 10^ C. [about 50° F.j. The surviving fish, put to- 

 gether in a common trough, are in good health." [Bulletin, March, 1884, 

 p. 308.] 



