158 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



the tin spout to enter the next compartment, a vertical fall of about 

 three-fourths of an inch. The downward movement which the water 

 hereby acquires changes its course so that, instead of flowing right off 

 along the surface as before, it now proceeds towards the bottom, thence 

 along the upward-inclined surface of the box, and then farther upward — 

 in brief, it receives a whirling movement in a vertical, instead of, as 

 heretofore, a horizontal direction. The eggs cauuot now longer remain 

 on the bottom, but must go with the current and be kept thereby in con- 

 tinual motion. The number of eggs injured in this way was very large; 

 however, the loss was not total, since they could, to some extent, collect 

 in the "eddies" of the hatching-box opposite the tin spout, also along 

 the sides of the box, which is movable. In order to secure motion in 

 the mass of eggs there is needed merely a brief pressure on the edge of 

 the box, which pressure also forces the water up through the bottom, 

 and I have determined to utilize this circumstance. Consequently I 

 have had constructed an appliance which, by communication with a 

 steam-engine, will furnish a uniform upward and downward movement 

 to the egg-boxes. This apparatus, however, was finished too late to be 

 tested during the more unfavorable condition of a too low salinity of the 

 water. 



It is essential, however, in this case, as well as under the former con- 

 dition, to keep the apparatus absolutely clean, and to remove the dead 

 eggs immediately. When there is a stock of 40,000,000 to 50,000,000 eggs 

 in the establishment this will involve considerable labor, of course ; but, 

 on the other hand, there is reason to believe that careful filtering of the 

 water before introducing it into the boxes will diminish the labor to a 

 considerable extent. 



Flounders. — As gravid flounders, chiefly Skrubbe,* were rather 

 easily procured, and the greater portion of the apparatus stood idle for 

 want of eggs, I resolved to make an experiment with these fishes also, 

 and so much the more because no attempt of this kind had previouslv 

 been made. The following table furnishes a synopsis of the results 

 accomplished in this direction : 



Table shotting the extent of flounder-hatching from March 6 to April 28, 1884. 



Date. 



Eggs ferti- 

 " lized. 



Total number 

 of fertilized 

 eggs. 



100, 000 



400, 000 



1, 150. 000 



1, 150, 000 



1, 750, 000 

 1,950,000 

 •I, 150,000 



2, 400, 000 

 2, 800, 000 

 2- 800, 000 

 2, 8U0, 000 

 2, 800, 000 

 3 300,000 



Rejected 

 eggs. 



150,000 



MOO, 000 

 400, 000 



I 

 Net stock of 

 fertilized 

 eggs. 



Young liber- 

 ated. 



100, 

 400, 



1,000, 

 955. 



1, 555. 



1, 705, 



1, 905, 

 2,010, 



2, 1 10, 

 1,710, 

 1 . 5G0, 

 1, .;.60, 

 1, 860, 



000 

 000 

 000 

 000 

 000 

 000 

 000 

 000 

 000 

 000 

 000 

 000 

 000 



' Pleuronectes flenus. 



45, 000 



50. 000 



145, 000 



150,000 

 200, 000 



Remarks. 



