296 



PLASMODROMATA AND SARCODINA 



Classification.' — The classification of the subkingdom Protozoa is 

 by no means satisfactory at present, but for remarks upon this 

 subject we refer the reader to Poche's article thereon written in 

 the Archiv fur Protistenkunde, vol. 30, in 191 3. 



The old classification was into four classes : (i) sarcodina; (2) mas- 

 tigophora; (3) sporozoa; (4) infusoria. 



The sarcodina move and capture food by pseudopodia; the 

 mastigophora by fiagella ; the sporozoa are parasites without motile 

 organs; and the infusoria move by means of cilia. When this 

 classification was brought into use, practically nothing was known 

 about the life-history of the protozoa, a more complete knowledge 

 of which is still required. 



Schaudinn's work with regard to the life-history of flagellates 

 having failed to be confirmed, and Hartmann's binucleate theory 

 having fallen into disuse, we have returned to Dofiein's classification 

 as set forth below. 



Among the blood parasites of man and other animals there are 

 found some wavy, thread-like organisms {Spirochcetes and Tre>^ 

 ponemata), with which must be classed some free-living forms whose 

 position, even in the animal kingdom, has been disputed. 



Most authorities believe that these forms are protozoa with a 

 low type of nucleus, butjso different are they from the ordinary 

 phyla of protozoa that, following Dofiein's and Fantham's sugges- 

 tions, we shall place them in a separate section, making them an 

 Appendix to the Mastigophora, though Calkins thinks it better to 

 leave them in their old position at present. 



Further, the old group of the Sporozoa Leuckart, 1879, contains 

 two such different groups of animals in its subdivisions into Telo- 

 sporidia and Neosporidia that it is justifiable to do away with this 

 combination, and to raise the two divisions to the rank of separate 

 phyla. 



Finally, the two nuclei of the infusoria are so totally different 

 in function from the nucleus or nuclei of the rest of the protozoa 

 that the Subkingdom is capable of being divided into two divisions :— 

 the Heterokaryota or infusoria; and the Plasmodromata, under 

 which heading come the other phyla. 



In the present work the following classification is adopted : — 



DIVISION A. PLASMODROMATA Doflein, 1901. 



Phylum I. — Sarcodina Hertwig and Lesser, 1874. 

 Phylum II.— Mastigophora Diesing, 1866. 

 Phylum III. — Telosporidia Schaudinn, 1900. 

 Phylum IV. — Neosporidia Schaudinn, 1900. 



DIVISION B. HETEROKARYOTA Hickson, 1903. 



Phylum V. — Ciliata Perty, 1852. 



Phylum VI. — Acinetaria Lankester, 1885. n 



