34 KEVIEWS. 



V. — On the Natural Position and Limits of the group Protozoa. 



1. — Die Klassen und Ordnungen des Thier-richs, wissenschaftlich 

 dargestellt in wort und Bild. Yon Dr. H. G. Bronn, Professor an 

 der Universitat Heidelberg. Erster Band, Amorphozoen. Leipzig 

 und Heidelberg, 1859. 



2. — Grundziige der Yergleichenden Anatomie. Yon Dr. Carl Gegenbaur, 

 Professor der Anatomie zu Jena. Leipzig, 1859. Erster Abschnitt, 

 Protozoa. 



3. — A Manual of the Sub-Kingdom Protozoa, with a general Introduc- 

 tion on the Principles of Zoology. By Joseph Eeay Greene, B.A., 

 Professor of Natural History in the Queen's College, Cork. Lon- 

 don, 1859. 



4. — An Essay on Classification. By Louis Agassiz. London, 1859. 



5. — Palaeontology ; or, a Systematic Summary of Extinct Animals, and 

 their Geological Eelations. By Richard Owen, E. E. S., &c, &c. 

 Edinburgh, 1860. 



Two authors, of high reputation, having recently expressed themselves, 

 in a somewhat remarkable manner, on the nature of the Protozoa, we 

 have been induced to bring forward the following general comments on 

 the constitution of the group in question. 



The Protozoa form one of the primary departments, or sub-kingdoms, 

 into which the animal world is divided ; that, in short, to which the 

 lowest forms of animal life belong. 



At the time of Cuvier, our knowledge of the humbler animal organisms 

 was not sufficient to enable that naturalist fully to appreciate the 

 importance and extent of this division. The Infusoria, (exclusive of the 

 Eotifers,) and the Sponges, (then placed among the Polypes,) may be 

 said to have constituted, in the Cuvierian arrangement, the germ of the 

 sub-kingdom Protozoa, as it now stands. - kt 



An early step towards the attainment of right views on the present 

 subject was made by Milne-Edwards, who, in his modification of the 

 system of Cuvier, sub-divided " Les Zoophytes" of that author into two 

 great sections: Eadiaires, and Sarcodaires. In the latter division he in- 

 cluded the two classes of Infusoria and Sponges. 



The name Sarcodaires had obvious reference to the researches of 

 another French naturalist, Dujardin, who introduced the term " sarcode"f 



* The term Infusoria is older than the time of Cuvier, and appears to have been first 

 made use of by Wrisberg, in his " Observationum de Animalculis Infusioriis Satura," 

 1765, although the German equivalent of the same word had, two years before, been in- 

 troduced by Ledermiiller. The Sponges received their earliest scientific treatment in the 

 works of Aristotle. The words K GTroyyog" *' <r<p6yyoc" and " arroyyia" occur in se- 

 veral of the older Greek authors. 



f See his " Histoire Naturelle des Infusoires," 1841, p. 35, et seq. 



