42. 



"both the oerca -:ia and cyst r,f Qejr curia tr i ypl vl s in the 

 tissues of 1 Ignorbis tribQlo is he also found that 

 re f 1 gyi . en ay a 1 d in the Bame snail. I 



reflexo (p. 42), Faust (1917) found Cercaria trisolenata 

 its cyit in the same host, occurring both in ^h 



rb is ^rxvolvi^ K rt also found the cyst of 

 a bi f Isxain the tissues of its >-iost beside 



I 

 Gerc^ri i^* j'rora tho above and othar nimilar Tidenoe f 



I believe that a?? iaor<9 ealiinoatoiaQ life oynles are partially 



or corapletely Jmo^n that ^ncy^tment in the same host will 

 be found to be M common family oharat<nristio. 



It oft^n happens that th oeroariae escape from the 

 nail only to r center the same speoimen to form the cyst, 

 However, sinoe 34 per oent of the snailn containing cysts 

 had only this ta% it is evident t^iat the cercarine need 

 not reenter the 8-ime fnail from ^hich they cnoae. This 

 leaving and reentering seerae to be an unn*eesary condition, 

 equivalent to going up hill to go down again* It is 

 worse than that, sinoe thMe is i decided wa??te of c 

 and thus the possibility of the continuation of the life 

 cycle ie lessened* It is certainly oonser votive tc say 



t many more oeroariae fail to find another suitable host 



th ei r 

 or / ^?a back to the s<a*ae snail thmn those th^i succeed* 



-jh a waste of oeroariae ^ould be entirely ^ voided if 

 the oercariae encysted in the same snail* Faust (1917, 

 p. 89) found that Ceroaria. b 1 f 1 *m encysted within the host, 



_ . *M IM. 



immediately upon brewing thru the birth-pore of the redia* 

 Such a step aeeras nn obvious shortening lively to ta^e place. 

 I believe thit it does taKe place quite often with the 



