308 American Fisheries Society 



the cage just described, and Numbers 11, 12 and 13 taken to 

 the Homer station and kept under observation. 



Examination was made of the pike perch at the Homer 

 station every two weeks during the winter. Any decrease 

 in the number of glochidia carried could not be detected, and 

 inspection of sediment from the bottom of the tank failed 

 to disclose any young mussels. 



Pike perch No. 4 died March 31, 1920, or 225 days after 

 infection. At the time of its death it carried 3,495 mussels 

 on its gills. Several, scraped off and placed in water, dem- 

 onstrated that they were alive by thrusting out the ciliated 

 foot. Pike perch No. 2 died May 3, 1920, or 258 days after 

 infection. The glochidia on the gills of this fish were not 

 counted, but were conservatively estimated to be 3,000. 

 Numbers 11, 12 and 13 died on different dates between 

 March 18 and April 24, 1920, from 195 to 233 days after 

 infection. None had dropped any appreciable number of 

 glochidia, and all were carrying living mussels at the time 

 of death. It should be explained that the death of these 

 fishes was due to lack of food and attacks of fungus when 

 the water became warmer, 46 to 48 degrees F. 



On June 3, 1920, the cage containing the companion 

 fishes was raised from the lake bottom. Seven of the eight 

 pike perch were alive and vigorous; the eighth fish was dead 

 but its body was recoverable. Pike perch No. 5 was identi- 

 fied by the tag, but Numbers 1 and 3 could not be identified 

 because they had lost their tags. The gills of No. 5 were 

 almost free from glochidia; three were removed, and, being 

 placed in water, were active after two hours. This took place 

 289 days after Numbers 1, 3 and 5 had been infected. 



Fish No. 6 was also identified by means of the num- 

 bered tag. Although it had dropped nearly all glochidia, two 

 were removed alive. The remaining fishes had lost their dis- 

 tinguishing badges and could not be identified positively. 

 Each fish resembled the two on which the tags had remained, 



