The third method was also experimental. It consisted 

 in hitching the echinostome eggs in Syracuse dishes in which 

 most of the water was changed daily. Shortly before the 

 miracidia were due to emerge, young snails were placed in th 

 Syracuse dishes with the eggs. These young snails were rais 

 from <3ggs in aquaria whioh in no way could have become infec 

 They "/?re about six months old at this time. 



The fourth method was that of examining the various 

 suspected water birds from the lake from which all the snail 



^ y (i <" / '. - ! 



were taken arid particularly those birds which stay on the la 

 nearly or all the year around. The following water birds 

 were examined: one specimen of lo r m cp lumbi anus (Ord. ); one 

 ^ Anger an us semipalinata (Lath.); three mud hens, gul i o a 

 amerioana (Gmel) ; one shoveller duck. Spatula clyffeaXa (Linn 



one mallard, Anas jpl a ty r/ lynoho Q Linn; two ri.' dy ducks, 



"" 



Sri amatura j amaicens.lH (Gmel.); and two bluebills or more 

 accurately the American Scaup, Marila marila (Iiinn.). All 

 but the American scaup gave negative resul ts for eohinostome 

 Jrom one of these two dti^e, adult echinostomes were cbtaine 

 which proved to be the same species as those gotten from 

 the experimentally fed ducklings* 



The tracing cf the excretory system of the cercaria 

 was accomplished by using the method described by Cort 

 (1918). This method of using living specimens for study by 

 placing them under a No. 1 cover slip, although on the 

 whole advantageous, h*s a decided disadvantage since most 



