PLASMODKOMA AND CILIOPHORA 157 



(1900) into the Telosporidia and Neosporidia. It appears, however, that 

 these two groups are so fundamentally different that it is better to follow 

 Hartmann (1907) and place the Neosporidia in a separate class, for which 

 Doflein's name Cnidosporidia may be employed, and to reserve the 

 Sporozoa for the forms included in Schaudinn's group Telosporidia. The 

 class CNIDOSPORIDIA includes parasitic Protozoa, which are either 

 amoeboid or almost, if not entirely, motionless. They produce, by a com- 

 plicated process of development in which several cells take part, very 

 characteristic encysted stages or spores which are peculiar in possessing 

 special bodies called polar capsules, from which long filaments can be ex- 

 truded. The class SPOROZOA also comprises parasitic forms, which 

 reproduce characteristically by schizogony. After syngamy the zygote 

 gives rise to a number of sickle-shaped sporozoites. These are either free 

 within the oocyst which forms around the zygote, or they are enclosed in 

 a number of secondary cysts, the sporocysts, which are formed inside 

 the oocyst. Schaudinn included the Sarcosporidia in his group Neosporidia. 

 These parasites, however, have little in common with the true Cnidosporidia, 

 and though they produce bodies which are called spores, these are structur- 

 ally quite different from those of the Cnidosporidia. In fact, very 

 liUle is known about the true nature of the Sarcosporidia, which will be 

 considered with certain other parasitic forms (Haplosporidia, Globidium) 

 of undetermined affinities. 



B. SUB-PHYLUM: CILIOPHORA DOFLEIN, 1901. 



Ciliophora is the name given by Dofiein to the second of the two sub- 

 divisions into which he divides the Protozoa. The organisms included in 

 this group have a comparatively complex structure, and in this respect 

 may be considered to be the most highly specialized of the Protozoa 

 (Fig. 70). The body is not, as a rule, subject to changes of shape, unless 

 as a result of external pressure, there being a definite body form for each 

 individual. The most characteristic feature is the possession of numerous 

 hair-like processes, the cilia, which cover either the whole or only part 

 of the body surface. The cilia are used as organs of locomotion, or for 

 producing currents in the water for the intake of food. They may also 

 serve as organs of special sense, such as taste or touch. 



The cytoplasm is differentiated into an endoplasm, which contains the 

 nuclei, contractile vacuoles, and food vacuoles, and a highly-organized 

 ectoplasm. The latter consists of a superficial membrane, the pellicle, 

 within which is a layer containing myonemes or contractile fibres, spaces 

 and canals of an excretory system, basal granules from which the cilia 

 arise, and sometimes trichocysts, which are small bodies from which 



