Plate II. 



Tetrancistrum sigani. 



11. Sernidiagraminatic representation of an entire worm killed under the pressure 

 of a cover slip ; dorsal view. 



12. Caudal hooks in natural position. X290. 



13. Caudal hooks as spread out. X290. 



14. Reproductive organs in dorsal view. x2U0. 



15. Glutinous penis and accessory parts. xGOO. 



