THE CILIATE INFUSORIA. 



35 



ers, so that when the organism has by means of its hollow 

 armri or tentacles caught some 

 Infuijorian, the arms con- 

 tract, draw the victim nearer 

 to the Acineta, and when the 

 suckmg disk at the end of the 

 arms has penetrated the skin, 

 the contents of the body of 

 the Inf usorian are sucked into 

 the food-cavity of the Acine- 

 ta ; on the other hand, in 

 some AcinetEe a portion of the 

 arms are simply prehensile. 

 These animals are in their 

 adult phase quite unlike the 

 Flagellata or Ciliata, but the 

 young are developed within 

 the parent and are provided 

 with cilia, being at first free- 

 swimming, and afterward 

 fixed by a long stalk. The 

 Acinetm sometimes self -di- 

 vide, sending oif from the 

 free end of the body a ciliated 

 Acinete ; they have also been 

 seen to conjugate. 



Order 3. Ciliata (Infuso- 

 ria). — A common type of this 

 group and one easy to obtain 

 by the student is Parame- 

 cium (Fig. 24), observed in 

 infusions, or moving rapidly 



, 1 -i J . « 1 . Fig. 24. — Faramecium caudatum. A 



over the bodies OI larger am- view from the dorBal side, magnified 340 



, i„ „.i,:„-u !.„ 3„,. 4.i,„ diameterB. .HI the head; T, the tali; m, 



maiS which may be under the the mouth; m to g, the throat; a, the po8- 

 miprnspfinp Tficnire '24. rpn- terior opening of the digestive cavity; <»' 

 juioiubcupe. JTiguie .«* jep the anterior and c» posterior contractile 

 rpsPTits Pnrnmpriiim rniirln- vesicles; I, II, III, the radiating canals of 

 xesenih jraramecmm cauaa ^,. „ ,^^ reproductive organ; v. the 



tum Ehrenberg. This ani- gblfe'^Sto^H'j^ciark''^^^''''''''™'*" 

 malcule is a mass of proto- 

 plasm, representing a single cell. In the body-mass are ex- 



