84 American Fisheries Society 



of the second lot of fishes were observed to be free from glochidia 

 within 27 and 32 days, respectively, after infection. Others con- 

 tinued to carry as late as October 1st (92 days) and were kept in 

 the enclosure for further examination. 



From this it is believed that the least time for metamorphosis 

 is required by glochidia taken from the parent shortly before the 

 time when the parent would normally discharge the spawn prepar- 

 atory to refilling the marsupial pouches, that is, during the month 

 of July. The instances in which certain fishes infected July 1st 

 dropped some mussels within 2 weeks and carried others 8 or 9 

 weeks, are explained by the fact that both old and new glochidia 

 from several mussels had been used in the infection. 



Late summer infections, those August 5th, August 19th and 

 September 4th, require long parasitic periods, since fishes, when 

 examined October 1st were found to be still carrying almost the 

 original infection. 



Glochidia placed on fish May 20th, 1919, grew to be mussels 5.5 

 millimeters long on July 26th (67 days); 11.0 millimeters long on 

 August 27th (99 days), and 17.0 millimeters long on October 1, 

 1919 (134 days). 



It is still too early to state the number of mussels raised per fish, 

 but it is expected that this can be done before the close of the 

 season. 



