THE GILIATE INFUSORIA. 



35 



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

 arms or tentacles caught some 

 Infusorian, the arms con- 

 tract, draw the victim nearer 

 to the Acineta, and when the 

 sucking disk at the end of the 

 arms has penetrated the skin, 

 the contents of the body of 

 the Infusorian 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 

 Ac i net (B sometimes self -di- 

 vide, sending off 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 rapidlv 



, -i -i -i -, . Fig. 24. Paramecium caudatum, A 



OVer the bodies Of larger am- view from the dorsal side, magnified 340 



mals which may be under the diameter - * the hea(1: ^ the tai1 ' 



the mouth; m to g, the throat; a, the pos- 

 terior opening of the digestive cavity; cp l 

 the anterior and cv posterior contractile 



microscope. Figure 24 rep- 

 resents Paramecium cauda- wl; n the reproductivc organ 



tum Ehreilberg. This aili- iTO vibrating^ilia at the edge of the ves- 



malcule is a mass of 



is a mass of proto- 

 plasm, representing a single cell. 



tibule. After H. J. Clark. 



In the body-mass are ex- 



