THE SPOROZOA 167 



than to the Flagellidia, but the conjugation processes are much more 

 like those of the Flagellidia. Haeckel follows Biitschli in regarding 

 the Sporozoa in this light, and derives them from the Phytoflagellida 

 through adaptation, first to a saprophytic and then to a parasitic mode 

 of life. Wasielewsky also favors the flagellate origin, basing his opin- 

 ion, however, upon the uncertain ground of flagellated swarm-stages 

 of certain Sporozoa as well as upon the general resemblance to the 

 Astasiidae. In general, however, it must be admitted that there is 

 very little support for any one of these theories, and all attempts to 

 trace the origin of the Sporozoa upon the mere basis of their present 

 degenerate condition are highly speculative. 



CLASSIFICATION 



CLASS III. SPOROZOA. The Sporozoa are Protozoa which are never provided 

 with flagella or cilia in the adult state. They are always endoparasites in cells, 

 tissues, or cavities of other animals, and food is taken in by osmosis. Repro- 

 duction is always by spore-formation, and germs {sporozoites) are produced 

 either directly from the parent, or indirectly through spores. 



Subclass I. TELOSPORIDIA. Sporozoa in which spore-formation ends the indi- 

 vidual life, the entire cell then forming spores. 



Order i. GREGARINIDA. Telosporidia possessing a distinct membrane, with 

 myonemes during adult life, locomotion being accomplished mainly by their 

 contraction. The young stages alone (cephalonts) are intra-cellular parasites, 

 the adults (sporonts) being found in the digestive tract or the body cavities. 

 Sporulation takes place after or without conjugation, but within a cyst which is 

 never formed while the parasite is intra-cellular. 



Suborder i. CEPHALINA. Gregarinida possessing an organ for attachment 

 (epimerite), and with or without septa dividing the cell into chambers. 



Tribe i. Gymnosporea. The adults are solitary or associated ; the sporozoites are 

 formed directly from the adult without encystment. 



Family i. Aggregatidae. Colonies consisting of two or more individuals. Several 

 residual protoplasmic masses are found during sporulation in each cyst. 

 Genera: Aggregata Frenzel ('85). 



Family 2. Porosporidae . The individuals are usually solitary. The sporozoites 

 are arranged in groups around a central residual mass. Genera : Porospora 

 A. Schn. ('75). 



Tribe 2. Angiosporea. Cephalina with well-developed spores, which are provided 

 with spore-membranes (epispores and endospores) . 



Family i. Didymophyidae . Chain-forming aggregates, two individuals being so 

 closely joined as to appear like one with three chambers. Genera : Didymophyes 

 Stein ('48). 



Family 2. Gregarinidae . The individuals are solitary or associated. The epimerite 

 is simple and regular. The cysts may or may not have spore-ducts. Genera : 

 Gregarina Dufour ('28) ; Gamocystis A. Schn. ('75) i Hirmocystis Le"ger 

 ('92) ; Hyalospora A. Schn. ('75) ; Euspora A. Schn. ('75) ; Sph&rocystis 

 Le*ger ('92) ; Cnemidiophora A. Schn. ('82) ; Stenophora Labbe ('99). 



Family 3. Dactylophoridae . The epimerite is asymmetrical and irregular. Genera : 

 Rhopalonia Leger ('93) ; Echinomera Labbe ('99) ; Trichorhynchus A. Schn. 

 ('82) ; Pterocephalus A. Schn. ('87) ; Dactylophorus Balbiani ('89). 



Family 4. Actinocephalidae . The individuals are always single. The epimerite is 



