190 The Philippine Journal of Science lais 



and also some among the Rhizopoda, but pressure of other duties 

 and lack of space make it seem undesirable to take up those 

 matters here, so Calkins's classification will be adhered to 

 throughout. 



Many schemes of classification have been proposed for the 

 Protozoa, and nearly every author of prominence has adopted 

 a plan to meet his own ideas. The best of these systems have 

 as their basis the organs of locomotion and their modifications. 

 These define the principal groups or subphyla, further grouping 

 being carried out on the basis of other characteristics. Under 

 the system of Calkins, the phylum Protozoa is divided into four 

 subphyla (classes of Minchin) : the Sarcodina, or protozoa having 

 pseudopodia as organs of locomotion; the Mastigophora, whose 

 motile organs consist of flagella ; the Sporozoa, having no special 

 organs of locomotion in the trophic stages; and the Infusoria, 

 having motile organs in the form of cilia. These groups will be 

 further defined later on. 



SUBPHYLA OF THE PROTOZOA 



SARCODINA. — Protozoa having motile organs in the form of changeable 

 protoplasmic processes known as pseudopodia. These may be either 

 simple or supported by a central axial filament (p. 194). 



MASTI60PH0KA. — Protozoa having motile organs in the form of one or more 

 vibratile or undulating processes known as flagella (p. 199). 



SPOROZOA. — Exclusively parasitic protozoa, reproducing mainly by spore 

 formation (p. 203). 



INFUSORIA. — Protozoa having motile organs in the form of flexible, vibra- 

 tile protoplasmic processes known as cilia. These may be modified 

 to form cirri, membranes, and membranelles. Dimorphic nuclei 

 (macro- and micronuclei). Some forms are provided with tentacles 

 in the adult stage (p. 208). 



TABULAR VIEW OF THE CLASSIFICATION OF THE PROTOZOA 



Subphylum SARCODINA (p. 194). 

 Class Rhizopoda (p. 195). 



Subclass Proteomyxa (p. 195) . 

 Genus Plasmodiophora. 

 Vampyrella. 

 Nuclearia. 

 Subclass Mycetozoa (p. 195). 

 Order Acrasiffi (p. 195). 



Filoplasmodia (p. 195). 

 Myxomycetes (p. 195). 

 Subclass Foraminifera (p. 195). 

 Order Gromiida (p. 195). 



Astrorhizida (p. 195). 

 Lituolida (p. 195). 

 Miliolida (p. 196). 



