198 CLASSIFICATION OF THE INFUSORIA. 



With scarcely an exception, none of the generic types included in Stein's 

 three family groups just cited possess this ingestive property, and are 

 consequently here refused admission within the essentially zoologic section 

 of the Infusoria. 



With reference to the remaining twelve Flagellate family groups included 

 in Stein's classificatory system, some few, such as those of the Dendromo- 

 nadina, Spongomonadina, Craspemonadina, Bikoecida, and Chrysomonadina, 

 beyond doubt contain genera that exhibit well-marked natural affinities. 

 Others, such as his Monadina, Astasi^e, and Scytomonadina, comprise the 

 most incongruous elements, mouthed and mouthless, uniflagellate, biflagel- 

 late, and multiflagellate animalcules being indifferently intermingled. 

 Phalansterhim, a uniflagellate collared monad, is interpolated amongst the 

 otherwise natural biflagellate group of the Spongomonadina, and with which, 

 excepting for the secretion of a similar gelatinous zoocytium, the animal- 

 cules possess nothing in common. Poteriodendron, again, while represented 

 in the figures given and accompanying index as possessing a collar homo- 

 logous with that of Codosiga and its allies, but somewhat differently situated, 

 instead of being placed among the Craspemonadina, is included in the family 

 group of the Bicosoecidae. Stein's apparently inconsistent location of Pote- 

 riodendron is nevertheless important, since it entirely supports the views 

 concerning this type expressed on a succeeding page, and where it is held 

 by the author to be actually a biflagellate organism closely allied to 

 Bicosccca and synonymous with the Dinobryoii petiolatimi of Dujardin and 

 the Stylohryon petiolaUnii of De Fromentel. The separation of the two 

 genera Epipyxis and Dinobryon from all the other generic groups of the 

 Chrysomonadina, with which in structure they fundamentally agree, is 

 entirely artificial, 



The scheme proposed by Stein for the subdivision into groups or orders 

 of the Ciliate section of the Infusoria, such orders being distinguished by 

 the titles of the Holotricha, Heterotricha, Hypotricha, and Peritricha, leaves, 

 so far as our present knowledge extends, nothing to be desired, and is 

 cordially adopted in the present work. 



The system introduced by the author, and adopted for the purposes of 

 classification and taxonomy throughout this treatise, alone awaits notice. Its 

 chief features of distinction, as connected with the several schemes previously 

 enumerated, are naturally connected with the class Flagellata, upon which 

 the author's attention has for many years past been more exclusively con- 

 centrated. The result of such investigation has been the discovery of forms 

 differing 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 foregoing 

 ordinal appellations of the class Ciliata, has been rendered necessary. The 

 broad grounds upon which these new orders are established — chiefly based 

 upon the modifications exhibited by the oral system and appendicular struc- 

 tures — have been already discussed in Chapters II. and III., and are also 



