FISH BREEDING. 679 



■whore the dwelling is located; and from this point the surplus water 

 returns, by its own gravity, through pipes into the third pond. 



Natural Production— Spawning-Beds.— In the second and third ponds 

 are located the spawning-beds. Here are constructed, where the water 

 falls from the first pond into the second, and from the second into the 

 third, and where the spring empties into the third pond, respectively, 

 wooden troughs, the bottoms of which are covered with gravel, and over 

 this gravel a gentle and rippling current of water is conducted into the 

 ponds themselves. Both the first and second ponds are enclosed in rough 

 coarse buildings, the object being the same as in the case of the hatch- 

 ing-building already described. 



The Trout begin to exhibit signs of the sexual instinct about the middle 

 of October. About the 1st of November the female begins to deposit her 

 eggs, and the operation is continued until the middle or latter part of De- 

 cember. She is attended by the male until the operation is completed, 

 and the egg-depository is housed in gravel and there protected against 

 invasion. At first the fish are seen emerging in groups (the females being 

 attended by the males) from the deep water, and approaching the localities 

 whose conditions are adapted to the work they have to do. These condi- 

 tions are, shallow water, not frequented by foragers, and a material 

 (gravel) which they can readily move, and with which they can cover up 

 and conceal the impregnated ova ; and they seem to understand that these 

 conditions are to be found in rippling water. Here, left to themselves, by 

 the joint labor of the male and female a cavity is effected in the gravel, 

 the eggs are deposited therein and the milt of the male is ejected over the 

 deposit. Then the water is agitated by quick movements of the tail of the 

 fish, so as to effect a perfect impregnation of the eggs ; the surrounding 

 gravel is then gathered over the spot so as to conceal the deposit, and the 

 female, accompanied by the male, having completed the work of mater- 

 nity, returns into the deep water to restore the energies thus expended. 



Artificial Propagation. — Securing the fish and expressing the spawn is 

 done in this wise : As soon as the Trout have entered the spawning-trough, 

 a gate at the lower end is let down, and the fish, thus close prisoners, are 

 relieved of all further duty. The operator then secures his subjects 

 with a small dip-net, and places them in a vessel of water, which 

 he will find contains a fair proportion of each sex. Having previously 

 provided a smaller vessel, with just enough water to cover the bottom com- 

 pletely, he then takes the females one after the other, and grasping them 

 by the gills, suspended over the small vessel, tail downwards, with the 



