J)iAuiiAM illustrating iny hypothesis of the relations of the several 

 forms and stages of Cestode larvie deseriljed in llerdnian's 

 lleport. 



(The letters correspond to those in the above diagrams. Those 

 marked A', A", B', and J' are regarded as parallel stages to 

 A, B, and J.) 



Species I. Tetrarhynchus union! factor. 



A D 



Kgg, (?) swallowed by h^vvaX Tetrai-hpt- 



Tj 1 ,-> . 1 i. 1 chiis unionifactor, in 



rearl-Oyster ; hatch- ^ , , , ,. 



> and around the all- 



ingout in intestine to ^^^^^^^^.^ ^,^„^^, ,^j. ^,,,. 



•^fi""""-' \ Pearl-Oyster. 



Adult Tetrnrhyiichus 

 unionifactor in ali- 

 mentar}' canal of lihi- 

 noptera javanica and 

 G-injIi/mosfoma con- 

 color. 



Species IJ. Ti/loccplial nui hi.<lijtcans. 



B 



c-) 



Hoi nidi's fice- 

 swininiing- 

 ^liirva. 



/ 

 A' /"' ^x, C 



Egg, (?) hatching in/"^ N^ Globular cysts, T^y/o- 



st'a-water to become B • cephcdum ludificans, 



or (?) swallowed by~~ " -> in liver and connective 



Pearl-Oyster to be- , tissues of the Pearl- 

 come C \ Oyster. 



\ J / 



An adult Tyloce- 

 phalam-ViVe form in 

 one of the oyster-eat- 

 ing Elasmobranchs, 

 probably Aetohath 

 navinari. 



Puuc. ZooL. Sue— 1 9 1 2, No. XIX, 19 



