86 



PROTOZOOLOGY 



Fig. 33. A filopodium of Lieberkuhnia, capturing and digesting 

 Colpidium colpoda (Verworn). 



Similar observation was made by Schaudinn in the heliozoan 

 Camptonema in which several axopodia anastomose to capture a 

 prey (Fig. 163, d). In the holozoic Mastigophora, such as Hyper- 

 mastigina, which do not possess cytostome, the food-ingestion is 

 by pseudopodia also. 



The food particles become attached to the pseudopodium and 

 are held there on account of the viscid nature of the pseudopodi- 

 um. The sudden immobility of active organisms upon coming in 

 contact with pseudopodia of certain forms, such as Actinophrys, 

 Actinosphaerium, Gromia, Elphidium, etc., suggests, however, 

 probable discharge of poisonous substances. In the Suctoria which 

 lack a cytostome, the tentacles serve as food-capturing organel- 

 lae. The suctorial tentacle bears on its distal end a rounded knob 

 which, when it comes in contact with an actively swimming cili- 

 ate, stops the latter immediately (Parapodophrya typha, Fig. 

 287, a). The prehensile tentacles of Ephelotidae are said to be 

 similar in structure to the axopodia, in that each possesses a bun- 

 dle of axial filaments around a cytoplasmic core (Roskin). These 

 tentacles are capable of piercing through the body of a prey. In 

 some suctorians, such as Choanophrya (Fig. 291, a), the tentacles 

 are said to be tubular, and both solid and liquid food materials are 

 sucked in through the cavity. The rapidity with which a tentacle 

 of a suctorian stops a very actively swimming ciliate is attributed 

 to a certain substance secreted by the tentacles which paralyzes 

 the prey. 



