ii2 PARAMCECIUM, STYLONYCHIA, AND OXYTRICHA 



In Fig. 21, B, a few trichocysts (trcti) are shown in the ex- 

 ploded condition, i.e. with the threads protruded. Most 

 likely these bodies are weapons of offence like the very 



FIG. 22. Stages in the conjugation of Paramcecium aurelia. 



gul, gullet : n, nuclei of gametes ; p, paranuclei of gametes ; p l , / 2 , 

 products of division of paranucleus ; p. n, those products of division of 

 the paranucleus which afterwards unite to form the reconstituted nucleus ; 

 /. /, those forming the reconstituted paranucleus. 



For full explanation see text below, p. 113. (After Gruber). 



similar structures (nematocysts) found in polypes (see Lesson 

 XXII. Fig. 52). 



Paramoecium multiplies by simple fission, the division of 

 the body being always preceded by the elongation and 

 subsequent division of the nucleus and paranucleus (Fig. 21, 

 D). As shown in the figure nuclear division is direct, there 

 being no formation of karyokinetic figures. 



