VORTICELLA. 19 



ing motion, and thus gradually aggregate them into a 

 little food ball. 



6. From time to time the contractions of the body drive 

 these pellets into the endosarc, where they form food 

 vacuoles. 



7 . As the currents of the endosarc carry the food vacu- 

 oli around the body, the water and soluble portions are 

 digested out and absorbed, and the indigestible poition 

 is linally accumulated near the upper surface of the crop, 

 into which it is finally drawn by a contraction of the body, 

 to be expelled through the vestiljule. 



c. Make a sketch showing these points. 



XII. As a rule only one contractile vesicle is present 

 near the upper end of the bell. It presents no features 

 which cannot be studied to better advantage in Pai^amoe- 

 cium. 



XIII. The endoplast is rather diiEcult to find in a liv- 

 ing specimen ; but it may be rendered visible by adding 

 a drop of dilute acetic acid to the drop of water which 

 contains the animal. It is a long, curved, club-shaped 

 body (Fig. 4, h), which extends around two-thirds or 

 more of the circumference of the body, and lies between 

 the ectosarc and endosarc, as shown at c in Fig. 5. It is 

 transparent, dark-colored, finely granular. There is no 

 endoplastule as there is in Paramcecium. 



IV. THE MULTIPLICATIOX OF VORTICELLA. 



The beginner cannot hope to overcome the diflEiculties 

 which attend the attempt to trace all the stages in the life- 

 history of an Infusorian ; but a little patience will enable 

 him to find isolated examples of most of the points which 

 are to be noticed. 



