14 HANDBOOK OF PROTOZOOLOGY 



ably some Metazoa and Protophyta in his monographs, some 

 of his descriptions and figures of Ciliata were so well done that 

 they are of value at the present time. 



At the beginning of the nineteenth century the cyclosis in 

 Paramecium was brought to light by Gruithuisen. Goldfuss 

 (1817) coined the term "Protozoa," including in it the coelen- 

 terates. Ten years later there appeared d'Orbigny's systematic 

 study of the Foraminifera, which he considered as microscopical 

 cephalopods. In 1828 Ehrenberg began publishing his observa- 

 tions on Protozoa and in 1838 he summarized his contributions 

 in "Die Infusionsthierchen als vollkommene Organismen," in 

 which he diagnosed genera and species so well that many of 

 them still hold good. He excluded Rotatoria and Cercaria 

 from Infusoria. Through the studies of Ehrenberg the number 

 of known Protozoa increased greatly; he, however, proposed the 

 term "Polygastricha," under which he placed Mastigophora, 

 Rhizopoda, Ciliata, Suctoria, Desmids, etc., since he believed 

 that the food vacuoles present in them were stomachs. This 

 hypothesis became immediately the center of controversy, 

 which incidentally, together with the then-propounded cell 

 theory and improvements in microscopy, stimulated researches 

 on Protozoa. 



Dujardin (1835) took pains in studying the protoplasm of 

 various Protozoa and found it alike in all. He named it "sar- 

 code." In 1841 he published an extensive monograph of various 

 Protozoa which came under his observations. The term "Rhi- 

 zopoda" was coined by this investigator. The commonly used 

 term "protoplasm" was coined by Purkinje in 1840. 



The term Protozoa was given a distinct definition by Siebold 

 in 1845 as follows: "Die Thiere, in welchen die verschiedenen 

 Systeme der Organe nicht scharf ausgeschieden sind, und deren 

 unregelmassige Form und einfache Organization sich auf eine 

 Zelle reduzieren lassen." This definition is still followed today. 

 Siebold subdivided Protozoa into Infusoria and Rhizopoda. The 

 sharp differentiation of Protozoa as a group certainly inspired 

 numerous microscopists. As a result, various students brought 

 forward group names, such as Radiolaria (J. Muller, 1858), 

 Ciliata (Perty, 1852), Flagellata (Cohn, 1853), Suctoria (Cla- 

 parede and Lachmann, 1858, 1859), Heliozoa, Protista (Haec- 



