VORTICELLA (Bell Animalcule). 



Phylum I, PROTOZOA; class 5, INFUSORIA; order r, CILIATA. 



HABITAT. Vorticella is found in pretty much the same situations 

 as Amoeba and Paramcecium in ponds and pools of standing water. 

 Colonies or groups of the organism, distinguishable with the naked 

 eye, appear like tufts of whitish mold attached to sticks and leaves 

 submerged in the water. Some genera are marine. 



Technical Note. Mount on a glass slide a bit of vegetable substance 

 from water containing Vorticella, and study first with a low power 

 and later with a higher power of the microscope. 



APPEARANCE. Look for isolated organisms or groups of the same 

 having a bell-shaped body and a long slender stalk. The stalks will 

 be attached to some object and may be tangled up somewhat from 

 your manipulation of the material hi mounting it. 



DETAILS. Sudden contractions of the stalk, accompanied by 

 changes in the shape of the body, occur frequently, especially if the 

 slide be jarred by tapping it lightly. Study carefully the appearance of 

 stalk and body in the normal and hi the contracted position. Note 

 the following: 



a) A circlet of cilia around the distal end of the body. These hair- 



like threads of protoplasm are in constant motion except when 

 the animal is contracted. The motion serves to maintain a food- 

 bearing current of water; also if any individuals have been broken 

 from their stalks they will be observed to swim about by means 

 of the cilia. Look for some such stalkless specimens. 



b) The peristome, a sort of flaring rim or flange just outside the 



circlet of cilia. 



c) The disc, a convex, lid-like structure covering the mouth of the 



bell. Between the edge of the disc and the peristome on one 

 side is the mouth or vestibule leading into a gullet running 

 down into the inner protoplasm. Mouth and gullet are not 

 easily made out. 



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