Diagram illustrating Prof. Herdman's conclusions as to the 

 life-history of the parasites. 

 Species I. Tetrarhynchus unionifactor. 







Globular cysts in 

 liver and connective 



^ tissues of Pearl-O^'stei- 



( = Tylocephcdnm ludi- 

 ficans). \ 



\ 



-This transition is 

 doubted bj- Shipley. 



D 



Larval Tetrarhi/n- 

 cJius tmionifactor hi 

 neighbourhood of ali- 

 mentary canal of Pearl- 

 Oyster. 



Adult Tetrarhyn- 

 chus unionifactor in 

 alimentary canal of 

 Mhinoptera javanica 

 and Qinglymostoma 

 eoncolor. 



I 

 I 



Immature Tetra- 

 rhynchus in Halistes. 



J This stage is rejected by 



Shiple}', and is regarded 

 as collateral or acci- 

 dental bv Southwell. 



Species II. 



" Tetrarhynchus sp." 



G 



Smaller globular cj'sts 

 in connective tissues of 

 Pearl-Oyster {=Tylo- 



cephalum minus). 



Southwell considers 

 this the same species 

 as " C " above. 



H 



Possibly the smaller 

 Tetrarhynchus found 

 in the intestine of the 

 Pearl-Oyster, if it is 

 distinct from T. unio- 

 nifactor. 



