THE OPALIXID CILIATE INFUSORIAXS. 431 



woodhousL Among the Leptodactylidae, in Limnodynastes dorsalis 

 Kaff reports Protoopalma dovsaUs and P. acuta as present simultane- 

 ously ; in Ujyerollia viarmorata Eaff reports simultaneous infection by 

 Protoopallna " intestinaJis " and P. tenuis. Among the Gastrophry- 

 nidae we have one instance, an individual of Rhinoderma darwlnii 

 showing ZelJerieJIa darwlnii and Protoopallna rhlnodermatos. 

 Among the Ranidae, in Rana esculenta we frequently find together 

 Cepedea dwildlata and its form zelleri. Both Neresheimer and I 

 have formerly treated the latter as a distant species. 



No case of triple simultaneous infection is known. Of the eight 

 known cases of double infection, two show both the Opalinids be- 

 longing to the same genus, while in six cases the two Opalinids are 

 of different genera. In two of these six cases the Opalinids are of 

 the same subfamily ; in the other four cases they belong to different 

 subfamilies. It is of some interest to note that five of the eight 

 known cases of double infection are from species of Bufo., a genus 

 which is hospitable to all genera and subgenera of Opalinidae. 



9. A CHRONOLOGICAL REVIEW OF THE LITERATURE OF THE OPAL- 

 INIDAE, SUPPLEMENTARY TO THE CHRONOLOGICAL REVIEW PUB- 

 LISHED IN THE YEAR 1909 AS A PART OF THE AUTHOR'S PAPER 

 " OPALINA." 



M}^ former review of the literature of the Opalinidae included 

 papers published as late as 1908. This section of the present paper 

 will include references to a few books and papers omitted in the 

 former former review and will bring the summary of the literature 

 down to date. 



Ehrenberg (1831) refers to Bursarla as including some species 

 which have no mastication apparatus [Ehrenberg includes in the 

 genus Bursarla probably three or four Opalinidae; B. intestinaJis 

 (— probably Protoopallna intestlnalls, P. caudata, and Cepedea 

 dimidlata) and B . rmiaruni {= Opalina rananim)']. 



Pritchard (1842). The first edition of Pritchard's History of 

 Infusorial Animalcules, published in 1838, did not mention any 

 organisms which seem to be Opalinids. The second edition, four 

 years later, lists among the Bursarias two forms which are probably 

 Opalinidae, B. intestlnalls [—Protoopallna Intestinalis, P. caudata 

 or Cepedea dimidiata or all three] and B. ranarum [= Opalina ranu- 

 7^m'], though he describes each as having a small mouth. His B. 

 nucleus, from the recta of Rana temporarla and R. esculenta, is 

 probably BaLantldium rather than an Opalinid. Bursarla intesti- 

 nalis can not be " F. O.'' [O. F.] Miiller's Vlhrlo venniculus, as 

 Pritchard thinks. 



Pritchard (1852), third edition, places the genus Opalina in the 

 "family" Opalinoea in the first order. Astoma, of the class In- 



