432 BULLETIN 120, UNITED STATES NATIONAL MUSEUM. 



fusoria. The Astoma are defined as " Infusoria without mouth/' 

 The reference to Bursana is repeated verbatim from the second edi- 

 tion, but he adds further discussion as follows : " The species called 

 by Ehrenberg Bursaria ranarum^ is the Opalina ranarum of those 

 other authors [Purkinje and Valentin, Siebold, Dujardin] ; or in- 

 deed this Opalina appears the representative of B. ranarum^ B. 

 intestinalis, B. nucleus [the latter probably not an Opalinid], and 

 it may be also of other Bursariae of Ehrenberg, if, as some maintain, 

 they are only varieties and not species. * * * The Opalinxie are 

 characterized by being oval or oblong [not true of Protoopalina in- 

 testinalis and Cepedea dimidiata known at that time as Opalina 

 intestinalis], with an oblique cleft indicating a mouth toward the 

 anterior extremity (Dujardin) ; though, according to Siebold, they 

 have no mouth. They are parasitic chiefly in Frogs and Annelids, 

 and form but an artificial and provisional genus, for if mouthless, 

 they belong to the Parameciens; if they possess a mouth, to Leuco- 

 phrys.''^ [Opalina lumbrici and O. naiduni^ the two species described, 

 are neither of them true Opalinids. Of course the references to the 

 mouth are inadvertently reversed.] The references to Opalinidae, 

 given in the fourth edition (1861) of Pritchard's History of Infus- 

 orial Animalcules, are noted in Metcalf (1909). 



Stein (1854) denies that Opalina ranarwm is an independent or- 

 ganism, rather than a development stage of some higher animal, 

 because it has no mouth, a point which he discusses (p. 181), men- 

 tioning Ehrenberg's (1838) [mistaken] reference to the presence of 

 a mouth. He says Opalina ranarum shows no trace of the char- 

 acteristic Ciliata nucleus and reports that he never saw reproduction 

 by fission, but mentions observing a single one out of many hundred 

 individuals which was constricted, but in so unusual a direction that 

 it could be called only an injured animal. [Quite likely this was 

 the so-called oblique division, really morphologically longitudinal. 

 This is the earliest reference I have found to what may be fission 

 in O. ranarum^ but Ehrenberg (1838) had described transverse 

 division in '''' Burmria'^'' intestinalis^ = Protoopalina intestinalis, P. 

 caitdata or Cepedea dimidiata or probably all three. Ehrenberg's 

 references do not enable us to distinguish these three forms from one 

 another.] He also mentions the absence in Opalina ranarum of any 

 organs for attaching to the alimentary canal wall of the host. 



Bronn (1859) does not include Opalina among the Protozoa, but in 

 a footnote (p. 124) writes "Die wirklich Mund-lose Sippe Opalina 

 PV (=Leucophrys Duj., nicht Ehrb.), welche parasitisch in anderen 

 Wasser-Thieren lebt, besteht nach Stein's Nachweisungen aus Ent- 

 wicklungs-Zustilnden, theils von anderen Infusorien {O planarlum 

 von Trichodina mit7'a), theils vielleicht von Binnen-Wiirmern (Dis- 

 tomen ? ) . While there is here no mention of true Opalinids, the im- 



