40 PROTOZOA 



severe anemia associated with irregular fever, caused by Bartonella 

 bacillijormis. 



Order 4. — Myxosporidia cause epidemics in fishes and silk worms. 



Order 5. Sarcosporidia. — Sarcocystis is found in the muscles of 

 pig, mouse and man. It has been suggested that the larvae of flies 

 may transmit Sarcosporidia. 



General Considerations 



Protozoa are generalized single cells. They are differentiated into 

 ectoplasm and endoplasm. All organs of locomotion and defense 

 are from the ectoplasm. The seat of digestion and other functions 

 is the endoplasm. All Protozoa have a nucleus. There is generally 

 one but very often Protozoa are multinuclear. Other forms, 

 Infusorians, have two nuclei, one macronucleus and one micronu- 

 cleus. The former may be chain or dumb-bell shaped. 



Locomotion. — The organs of locomotion in Protozoa are pseu- 

 dopodia, flagella or cilia. The ciliates are extremely speedy in 

 movement, while many of the flagellates scull rapidly. Shipley 

 found that in the case of four amebae given ten trials, the fastest 

 moved 0.2 of a mm. in 60 seconds, while the slowest moved that 

 distance in 80 seconds. 



Nutrition. — Nutrition consists of capture and ingestion, digestion 

 and defecation. It may occur also by osmosis. 



(i) Many organisms can build up complex proteins from simpler 

 chemical materials. There are holophytic plant-like types in which 

 sunlight energy is used in synthesis and saprozoic forms in which the 

 protoplasm is built up from organic substances in solution. 



(2) Other organisms are entirely dependent on a supply of 

 protein ready made, obtained either by the holozoic method — by 

 engulfing and digesting other living organisms; or as parasites — by 

 feeding on digested foods. Parasites generally absorb their food in 

 an osmotic manner rather than by engulfing it. Some species of 

 Euglena are holophytic and others saprozoic. Some species in the 

 life of one individual are holophytic in the sunlight and saprozoic in 

 the dark. 



Ingestion. — The ameba type is enclosing; but vortex currents are 

 set up by the cilia in Ciliates while the Suctoria pour their endoplasm 

 into an animal, digest it and then suck it through their tentacles. 

 Wenyon states that enzymes probably aid in liquefying the protein. 



