4 8 



THE ANIMAL PARASITES OF MAN 



a similar course to that of allied forms (e.g., Euglypha, Centropyxis). It 

 commences by the cytoplasm issuing from the orifice of the shell and 

 assuming the shape characteristic of the mother organism, but in 

 a reverse position. The nucleus then divides by mitosis, when the 

 daughter nuclei move apart from one another. The chromidial ring 

 also divides into two portions by a process of dumb-bell like con- 

 striction. The one daughter nucleus remains in the mother organism, 

 the other moves towards the daughter individual, which then separates 

 from the parent. 



FlG. 13. Chlaniydophrys enchelys. a, free, motile form, showing nucleus, equatorial 

 granules, vacuoles and pseudopodia ; d, dividing organism, x 760. (After Cienkowski.) 



In this species plasmogamic union of two or more individuals (up to twenty) is 

 frequently observed. Such colonies may similarly divide, and in this way mon- 

 strosities frequently arise. When drying of the faeces, or deficiency of food occurs, 

 encystment takes place apparently spontaneously. The whole body, as stated by 

 Cienkowski, issues from the shell, assumes a spherical shape (probably with discharge 

 of water) and becomes surrounded with a thick membrane (fig. 14). After the addition 

 of water and the escape of the encysted Chlaniydophrys, a new shell must be formed. 

 Schaudinn, who has not given a more detailed description of the process of encyst- 

 ment in this species, but refers to Cienkowski and to similar observations made on 

 Centropyxis, states of the latter that the encystment takes place within the shell. 



The sexual multiplication is accompanied by shedding of all the 

 foreign bodies and of the degenerating nucleus. The protoplasm, 

 now contracting into a sphere, remains behind in the shell with the 

 chromidial mass. From the latter several new nuclei arise (sexual 

 nuclei) often eight in number. The cytoplasmic sphere then segre- 

 gates into as many spherical portions as there are nuclei present. 

 When they have assumed an oval form, two flagella develop at one 



