324 



I. IKEDA. 



families, the Opalinidae and the Anoplophryiidae. The former may be 

 defined as the Astomata which show no morphological differentiation of the 

 chromatin into generative and vegetative nuclei (hetcrokaryotc) and which 

 reproduce by muttiple division or repeated transverse segmentation ; latter 

 as those which are heterokaryote and multiply by ordinary fission. 



Now then, Metaphrya sagittae appears to be referable to the Ano- 

 plophryiidae Leg. & Dub. True, it somewhat approaches certain forms 

 {Opalinopsis, Chromidind) of the Opalinidae in the peculiar form ot mega- 

 nucleus, and that familly generally in possessing non-contractile vacuoles 

 instead of a single contractile vacuole j 1 ' but these points I am incline! to 

 view in the light of homoplastic convergence. The relatively complex or- 

 ganization of the new genus and species points to its being a highly 

 advanced representative of the Anoplophryiidae, on which account I have 

 chosen the generic name Metaphrya. 



CÉPÈDE has described a goodly number of entozoic ciliates as in- 

 habiting the body-cavities of many invertebrates. But none of them can 

 be said to be as genuine a coelom-parasite as the present species is. 

 I fetcropiirya astouiata Siedlecki has often been referred to as a coelom- 

 parasite, but the case is still open to doubt. 



In conclusion, I beg to express my warmest thanks for Professor 

 Ijima's kind advice and critics rendered me during my writing the 

 present paper. I also owe very much to Dr. Yatsu's kind help in obtain- 

 ing the literature. 



Zoological Laboratory, 



High Normal School, Hiroshima, 



January 191 6. 



1) According to / ohel' {I.e.), the single vacuole 

 nucleus of this form is complicately branched 

 state as was thought formerly to be the case. 



of Opalinopsis is contractile, and the single 

 into a network and is never in a dispersed 



