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I 98CLASSIFICA TION OF THE INFUSORIA.With scarcely an exception, none of the generic types included in Stein'sthree family groups just cited possess this ingestive property, and areconsequently here refused admission within the essentially zoologic sectionof the Infusoria.With reference to the remaining twelve Flagellate family groups includedin Stein's classificatory system, some few, such as those of the Dendromonadina,Spongomonadina, Craspemonadina, Bikcecida, and Chrysomonadina,beyond doubt contain genera that exhibit well-marked natural affinities.Others, such as his Monadina, Astasiae, and Scytomonadina, comprise themost incongruous elements, mouthed and mouthless, uniflagellate, biflagellate,and multiflagellate animalcules being indifferently intermingled.Phalansterinin, a uniflagellate collared monad, is interpolated amongst theotherwise natural biflagellate group of the Spongomonadina, and with which,excepting for the secretion of a similar gelatinous zoocytium, the animalculespossess nothing in common. Poteriodendron, again, while representedin the figures given and accompanying index as possessing a collar homologouswith that of Codosiga and its allies, but somewhat differently situated,instead of being placed among the Craspemonadina, is included in the familygroup of the Bicoscecidse. Stein's apparently inconsistent location of Poteriodendronis nevertheless important, since it entirely supports the viewsconcerning this type expressed on a succeeding page, and where it is heldby the author to be actually a biflagellate organism closely allied toBicosccca and synonymous with the Dinobryon petiolatum of Dujardin andthe Stylobryon petiolatum of De Fromentel. The separation of the twogenera Epipyxis and Dinobryon from all the other generic groups of theChrysomonadina, with which in structure they fundamentally agree, isentirely artificial.The scheme proposed by Stein for the subdivision into groups or ordersof the Ciliate section of the Infusoria, such orders being distinguished bythe titles of the Holotricha, Heterotricha, Hypotricha, and Peritricha, leaves,so far as our present knowledge extends, nothing to be desired, and iscordially adopted in the present work.The system introduced by the author, and adopted for the purposes ofclassification and taxonomy throughout this treatise, alone awaits notice.chief features of distinction, as connected with the several schemes previouslyenumerated, are naturally connected with the class Flagellata, upon whichthe author's attention has for many years past been more exclusively concentrated.The result of such investigation has been the discovery of formsdiffering so widely from the previously known representatives of this group,that the introduction of new distinctive titles having the value of Orders,and carrying with them as thoroughgoing a significance as the foregoingordinal appellations of the class Ciliata, has been rendered necessary.broad grounds upon which these new orders are established chiefly basedupon the modifications exhibited by the oral system and appendicular structureshave been already discussed in Chapters II. and III., and are alsoItsThe