THECAMCEBIDA 



327 



contractile and food vacuoles, and a posterior, with the nucleus. Reproduc- 

 tion is by ' bud-fission,' by which is meant that half the protoplasm protrudes 

 at the mouth and forms a new shell, and then separates from the other half, 



which retains the old shell. If 

 two forms reproduce by * bud- 

 fission ' close together, the 

 daughter cells may partially 

 coalesce (plasmogamy) , forming 

 large colonies of twenty or more 

 individuals. The parasites may 

 become encysted. 



The sexual process starts by 

 the extrusion of all foreign sub- 

 stances and the collection of the 

 remainder of the plasma and 

 the chromidia into the shell. 



The chromidial mass breaks up into a number of nuclei, never more than 

 eight, around which the plasma divides, forming swarm cells, which, developing 

 two flagella at one pole and escaping from the cell, conjugate with the swarm 

 cells of another individual, and then become encysted. When the cyst 

 ruptures under favourable circumstances, a little amoeba escapes, which 

 speedily forms a shell, and becomes in due course an adult Chlamydophrys. 

 If, however, it enters man it may remain in the amoeboid stage, and as such was 

 formerly called Leydenia gemmipara by Schaudinn. They were, however, 

 originally observed by Lieberkuhn in ascitic fluid taken from persons suffering 

 from a malignant growth, but he did not determine their true nature. Leyden, 

 again observing these cells in two similar cases, caused them to be examined by 

 Schaudinn. Lauenstein and Behla have also seen them in a case of cancer. 



They are spherical or irregularly polygonal, 3 to 36 jw in diameter, with 

 knobs projecting from the surface. They possess a distinct ectoplasm with 

 hyaline pseudopodia and a large vascular nucleus. Development takes place 

 by binary fission and gemmation (Fig. 65). 



Classification. — We have retained the old classification for the organism, 

 and have not placed it in the Foraminifera, as is done b}^ many authors. 



