oo. 



There are four ways by whioh stages other than the 

 adult of jJlohinostoma revo lutum can pass through the so - 

 winter season in the bay region of California* The first 

 way is by me ins of the egg. The second way is by means of 

 the rnother-redia. This could only result from eggs being 

 produced during the late summer, or early fall. During the 

 process of metamorphosis from the rairacidia into the mother- 

 redia, or after the enclosed daughter-redia had grown nearly 



to full size, the coming of winter we uld force the mother-red: 



* - th* 

 to remain dormant until spring. The third way is by means 



of the daughter- rediae, i.e., rediae containing cercariae., 



This could result only from eggs produced during mid-wuramer. 



owin f. 3 <*f t,fre ? 



There would be sufficient time from the mother-redlae stage 



and nearly enough time for the daughter -rediae to -produce 

 active ceroariae. The ls.o> of time to mature the ceroariae 

 would force the daughter -rediae to remain dormant until 

 spring. The fourth way is by means of the encysted agaaodisti 

 In a climate where there i8 a definite winter season, I dcubt 

 if the ^eoond and third ways of surviving the winter exist. 



The length of life of echinostome rediae has never been 

 determined, but doubtless they exist for a year or more. The 

 reason for this conclusion is, that since the average number 

 of active cercarime in the rediae is five, and the total 

 number of germ 'nails of all sizes is over a hundred, DTO- 

 bably closer to two hundred, it seems impossible that all 

 the germ balls could grow to maturity in less than a year's 

 time. That they exist in a dormant or semi -dormant condition 

 for the four months of the winter season is known. 



