PLATE 1 



EXPLANATION OF FIGURES 



1 Ventral aspect of sexually mature specimen. A, pharynx; B, anterior sack 

 of enteron; C, opening of vagina; D, sucking disc; M, mouth. X 75. 



2 Specimen loaded with nematocysts from Hydra attacking a living half of 

 an oligochaete. X 50. 



3 Oligochaete, partly ingested, being handled in such manner as that one end 

 is moving out of mouth of Microstoma, while the other end is being dragged into 

 mouth as shown by arrows. X 50. 



4 Prey lying end on and half ingested. X 50. 



5 Prey almost ingested. The Microstoma so badly gorged that the pharynx 

 of posterior zooid {Ph') is everted. X 50. 



6 Sagittal section of specimen with closed mouth. Anterior sac of enteron 

 conspicuous {A.S.). 0, oocyte. X 75. 



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