APPENDIX I. 



32. REVIEW OF TWO ADDITIONAL PAPERS UPON OPALINIDS, SUP- 

 PLEMENTARY TO SECTION 8. 



Since this paper went to press there have appeared in the Archiv 

 fiir Protistenkimde two papers based wholly or in part on studies 

 of Opalinids, which are of suflicient importance to review. 



Herfs (1922) studied Opalina ranamni among other Protozoa in 

 regard to their ability to adapt themselves to media less dense than 

 normal. He says that 0. ranarium has no contractile vacuole; that 

 it does not develop contractile vacuoles in fresh water, nor does it go 

 to pieces very soon, but lives and appears about normal in structure 

 and movements for a considerable time, up to 8 or 10 days may be 

 observed; but they do die sooner than Nyctotherus or Balantidium^ 

 both of which genera live with the Opalina in the anuran rectum. 

 These observations seemed to Herfs to oppose his hypothesis that the 

 pulsating vacuole enables Protozoa to pass into unaccustomed media 

 of less density than their normal medium without suffering injury 

 from too great osmotic imbibition of water. This hypothesis was 

 supported by the fact of increased activity in the pulsating vacuoles 

 in Protozoans so transferred to less dense media and also by the ap- 

 pearance anew of pulsating vacuoles in marine Protozoa when trans- 

 ferred to fresh water, though the normal animals in sea water did 

 not possess them. [Herfs need not abandon his hypothesis upon the 

 basis of opposed evidence from Opalina ranarum, for Konsuloff 

 (1922). in the next number of the same journal, described the system 

 of excretory vacuoles in this Opalina. There seems to be no rythm 

 of expulsion of excreta in any Opalinid, but there is occasional ex- 

 pulsion of both liquid and granules from the excretory pore. 0. 

 ranarum has numerous posterior excretory pores, according to Kon- 

 suloff.] 



Konsuloff (1922) reports extensive studies upon structure, be- 

 havior, and life cycle, chiefly of Cepedea [^^ Opalina^^] dimidinta 

 and Opalina ranarum. In Piitter's fluid they lived up to two months, 

 growinor and dividing. Gametes taken from the recta of tadpoles 

 passed normally through the sexual phases of the life cycle in 

 Piitter's fluid. They live longer if finely triturated ^g^ albumen is 

 added to the culture medium. " Opalina zelleri " is but a form of 

 0. [Cepedea dimidiata] not a distinct species (against Neresheimer 

 83103—23 30 ^^"^ 



