JLO. 



This greit variation in size is accounted for in two 

 ways, First, th:nt there is no very definite adult size 

 and second, that mature oercariae are produced long before 

 the rediae are full gro-#n. They possibly continue to 

 grow and to produce cercariae until tlielast of the germ 

 balls ar* matured. I am inclined to think that the first 

 explanation accounts for mont of the variation. 



The great variation in number of germ balls contradicts 

 Ssinitzirts theory (1911) that the number of cercariae 

 md germ balls of a given species fall within a certain 

 definite yet quite a large ranae. To a certain extent the 

 number of germ brills is determined by the size of the redia, 

 but there are plenty of exceptions* 



The shape of the reriia is usually that of a stocking 

 when viewed from the side (figs. 26 and 27) and apparently 

 straight when viewed do rsally or ventrally. . Many 

 other shapes may be found, however, as nearly ball -shaped, 

 very long and slender, or even constricted in one or more 

 places. The characteristic echinostome marXs are present 

 in all, however, if viewed from the jlroper angle. The 

 paired posterior protrusions are usually located near the 

 middle of the body. They extend ventrally, slightly laterall 

 an$ protrude about one-half the width of the redia. They 

 are rounded and no n -muscular, apparently never moving in a 

 forward direction. Upon these protrusions the redia usually 

 rests when placed in water, the anterior end often swaying 

 from side to side. At the anterior end a circular projection 

 or "collar" is found. This "cellar" is somewhat rigid and 

 into it the nee? of the redia may be partially withdrawn. 



