200 PROTOZOA 



tion and accompanied by a change of liost). The spores divide into 

 sporozoites. ^NluUiplicatiou without change of host (autoinfection) can 

 occur. 



21. The G>rgari)iiJd are temporary or permanent parasites in cells. 

 Coccidiic, HaDiosporiJa (cause of malaria, parasitic in blood corpuscles). 



2 2. The SarrosporiJa (Rainey's or ^liescher's corpuscles of mamma- 

 lian muscles) and MyxosporiJa (psorosperm capsules of fishes, psorosperm 

 = spore) live in tissues or hollow organs. 



23. The CiLi.VTA have numerous \ibrating processes, the cilia, a 

 cuticle, and hence fixed openings for the ingestion of food (cylostome) 

 and for extrusion of intiigestible matter (cvtop\'ge). 



24. Of great interest is the occurrence of two kinds of nuclei, a func- 

 tional macronuclcus and a sexual micronucleus. 



25. In conjugation portions of the micronucleus are exchanged and 

 accomplish impregnation. The macronuclcus degenerates and is replaced 

 by part of the fecundatetl micronucleus. 



26. The classification of the Ciliata is based on tire structure and 

 arrangement of the cilia. 



27. The HoJolriclia have similar cilia o^■e^ the whole body. The 

 Hclcrotricha have, besides the total ciliation, stronger cilia in the neigh- 

 borhood of the mouth (adoral ciliary spiral). The Pcritricha have only 

 adoral ciliation. The Hypolrirha have the ciliary spiral and rows of 

 cilia and coalesced cilia on the ventral surface. The Siuioria have cilia 

 only in the young, later they become attached and feed through suctorial 

 tentacles. 



APPENDIX. 



According to the evolution theory one should expect forms between die 

 Protozoa and JMctazoa. The Catallact.\ — spheres of ciliated cells which in 

 reproduction break up into single cells — have been described as such. Other 

 peculiar many-celled animals whose position in the system is dillicult to decide 

 are, Saliiiclla salve, Loluiiaiiflla catcniila, the Orthonectida and the Dicykmipa. 

 The Orthonectida and Dicyeniida have a manv-cclled ectoderm, enclosing a solid 

 mass of cells in the Orthonectida, a single giant cell in the Pievemida. Saliitflla 

 and LohmancUa consist of a single layer of cells enclosing a central digestive 

 space. Since the Dicycmida live as parasites in the nephridia of cephalo])ods, 

 the Orthonectida in worms and cehinoderms, it is possible that their low organi- 

 zation is the result of dc>j;eneration. Tr'whoplax adlncrcus, formerly placed here, 

 is discoid, consisting of twn epithelial hn'ers separated by gelatinous tissue. 

 It has recently been shown to be the lar\a of a medusa, Elcutlicria. 



