256 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



by hollowing out one side of a stout log, for nearly its entire length, and 

 covering the groove thus formed with- pieces of thick plank. The bark 

 should be allowed to remain undisturbed, where practicable, for a pro- 

 tection to the wood. The general arrangement of the flume and its 

 valves is indicated in the diagram. As the valves do not work auto- 

 matically, such a "plug-trunk" — as it is called — would appear to be 

 better adapted for ponds located in other than tidal regions. 







:^a= 



Fig. 



So much of the wood-work, in all these constructions, as is exposed 

 to the air, and particularly such parts as are subject to the alternate 

 action of the air and water, are liable to decay, and should be protected 

 by thick coatings of paint, or other preservative material. Such parts 

 as are imbedded in the earth will last for years. 



34.— SPAWNING OF CALIFORNIA MOUNTAIN TROUT, REARED IN 

 CONFINEMENT, FROM EGGS BROUGHT FROM McCLOUO RIVER. 



By FRANK W. CLARK. 



[From a letter to Prof. S. F. Baird.] 



Our rainbow trout have just commenced spawning. The first eggs 

 were taken day before yesterday, and we now have about 5,000. They 

 are from three-year old fish that were hatched and grown at this sta- 

 tion. There is a marked difference in appearance between these eggs 

 and those of same kind direct from California, ours being identical in 

 size and color with brook-trout eggs. 



Nortiiville, Mich., February 15, 18S3. 



