PROTOZOA. 



\m 



It has a mouth, whifli is situated at the exti-emity 

 of a groove running somewhat spii'ally from one end 

 of the l:)ody about two-fifths of the way to tlie other 

 end. The food balls 

 and contractile vesicles 

 described luider vorti- 

 cella are seen here. 



Tlie parannecium , 

 stentor, and vorticella 

 are among the largest 

 and most complex of 

 the Protozoa. Tlie 

 Amreba is one of the 

 simplest. It is fre- 

 quently found ci'awl- 

 ing in the ooze at the 

 bottom of a jxind, or 

 in mud that has l)een 

 taken from a pond. It 



is a mass of naked ijrotoplasm, wliicli seems to flow 

 along the surface of the glass slide on whicli it is 

 placed for observation. 



A small sti'eam of protoplasm will iiow out in one 

 direction and the rest of the l)ody will apparently 

 flow in the same direction and join the sti'eam ; otlier 

 stJ'eams, that luid i^reviously start(3d to flow out, 

 will flow l:)ack and join the l^odv, and all will flow in 

 the one dii-ection until the body has moved its 

 position. 



If a particle of food is found in the \va,y, the 

 body merely flows around it, enveloping it, and if 

 part of the sulistance that has been enveliiped is 

 found to I)e indigestible, the botly flows away from 

 it and leaves it. 



There is no head, n(j tail, no definite shape, no cilia, 

 no nKJuth. Food particles are usually seen enclosed 

 in the body, and a nucleus appears in most amcebse. 



