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22 BIBLIOGRAPHY.Contemporaneously with the earlier publications of Stein as above'recorded, mention must be made of the work of Maximilian Perty, ZurKentniss kleinster Lebensformen/ published at Bern in the year 1852.This treatise, like the earlier ones of Miiller and Ehrenberg, embracesan account, with illustrations, of a heterogeneous assemblage of microscopicaquatic beings, including Rotifera, Rhizopods, and Bacillaria inaddition to the ordinary Infusoria. These latter are, however, togetherwith the Rhizopoda, separated by Perty from the associated animal andvegetable organisms, and collated together as distinct classes of a subkingdom,essentially identical with the Protozoa of Von Siebold, butupon which he conferred the new title of the Archezoa. The class ofthe Infusoria is further divided by Perty into the two orders of theCiliata and Phytozoida, the former comprisingall the ordinary ciliateanimalcules, and the latter flagellate organisms generally, whether of ananimal or vegetable nature. The innumerable infusorial forms figured anddescribed by Perty were collected by himself entirely in the vicinity of theBernese Alps, and embrace many new species, some of which have not beensince met with, while a few, such as his Eutreptia viridis and MallomonasPlosslii, are delineated in this present volume after examination, for the firsttime, with the higher magnifying powers of the compound microscope inits present comparatively perfected state. Taken as a whole, Perty's illustrationsof the Infusoria, and of his Ciliata in particular, are exceedinglyrough and unsatisfactory, being inferior in many respects to those previouslygiven by Ehrenberg, and not to be compared with the contemporaneousones of Stein. The view taken by this author with reference to the organizationand internal structure of the Infusoria, is distinguished by its oppositionto both the unicellular one of Siebold and the polygastric one of Ehrenberg.In place of these, Perty substituted the interpretation that these microscopicbeings are composed of an aggregation of separate cells, none of whichhave attained their complete development, but remain indistinguishablyunited with each other. He thus, as presently related, anticipated to someextent the views adopted by Max Schultze in the same direction. Thepresence of any nervous, muscular, or other complex organization heentirely denied, as also that of a distinct internal parenchyma, the bodybeing described by him as composed wholly of simple contractile substance.The thickly ciliated cuticular surface of Stentor and other forms he neverthelesscompared to the ciliated epithelium of more highly differentiatedorganic types.The first onslaught upon the Acineta theory enunciated about thisdate by Stein, was delivered by Johannes Lachmann, who, in Miiller's'Archives ' for the year 1856, adduced testimony strongly in favour of theindependent organization oi Acineta and its allies, showing the characteristicmanner in which they preyed upon other Infusoria, and their mode ofreproduction through the separating of a portion of the central nucleus orendoplast. Corroborative evidence of a still more conclusive character, and