J. PISCICULTUKE AND THE FISHERIES. 421 



The total outlay for the appliances requisite for the fertil- 

 ization and hatching of the eggs and rearing of the young 

 fish scarcely amounted to $100, the heaviest item being a 

 pump, which could have been dispensed with had the natural 

 fall of the water been fully appropriated. The entire super- 

 vision of the establishment is performed by one person, who 

 is occupied for five months in the year, and for a few hours 

 only of the day. 19 A, July 20, 1872, 55. 



MENOBRANCHUS DESTRUCTIVE TO THE SPAWN OF THE 



WHITEFISH. 



One cause of the diminution of the number of whitefish 

 (Coregonus) in the great lakes is attributed to the destruc- 

 tion of their spawn by the Menobranclius lateralis, which, ac- 

 cording to Mr. George Clarke, of Ecorse, congregate on the 

 spawning-beds at the rate almost of one to the square yard. 

 When captured their stomachs are usually gorged with the 

 ova. According to this accurate observer, the eggs of the 

 Menobranchus are attached to the under side of pieces of 

 wood lying on the bottom of the river, and in clusters of 

 about one hundred each. They are hatched out in about 

 thirty days, more or less, according to the temperature of the 

 water. George Clarke. 



RENEWAL OF SALMON-PLANTING IN THE DELAWARE. 



During the year 1871 the experiment w 7 as tried, by some 

 public-spirited gentlemen of Philadelphia, of introducing sal- 

 mon into the Delaware River, and, although great anticipa- 

 tions of a successful result were formed, the effort came to an 

 untimely end by the death of the greater portion of the young 

 salmon in their transportation from the hatching-house on 

 the Hudson to the river itself. Not discouraged by the fail- 

 ure of the first attempt, the experiment has been repeated this 

 year under the direction of Mr. Thadcleus Norris, and 12,000 

 eggs, purchased from Mr. Samuel Wilmot and received on the 

 1st of April, have now been hatched out with a loss of only 

 about ten per cent., and have been placed in the Bushkill, a 

 tributary of the Delaware, near Easton. Two thousand fish 

 were saved of the last year's venture, and introduced into the 

 river, where, it is hoped, they .still survive. 



This year, instead of hatching the eggs at a considerable 



