I 



Keil — Smolt Period in Salmcnoids. 183 



scope. Such examinations disclosed many unusual organic dis- 

 turbances and lesions. The most important one in respect to the 

 subject under investigation was the peculiar distorted condition 

 of the lateral-line canals; and it is believed that the inability of 

 the parrs to withstand a high pressure was due to the unprotected 

 nature of these ducts at this stage of their development. 



These experiments, observations, and stocking experiences, 

 have given us a number of clearly established facts upon which to 

 exercise our common sense; and it should not be at all difficult 

 to understand what has happened to millions of our landlocked 

 salmon, steelhead and rainbow trout. Such fish planted while in 

 the parr stages in spring-fed lakes without tributary streams, are 

 unquestionably thrown away. Unable to find streams where nature 

 intended them to be at this age, or to descend to depths in the 

 lake where suitable food and temperature are to be found, these 

 fish swim aimlessly around in the surface water and eventually 

 disappear from one cause to another. 



