AMCEBA DYSENTERIC 213 



ferential cilia. In others a special muscular segment of the body 

 may exist. The suctorial tubes act also for motion at times. In 

 most protozoa two layers can be seen the ectosarc, and endosarc. 

 The ectosarc originates the movement, is concerned in the ingestion 

 and excretion of food, and the respiration. The endosarc, which 

 circulates slowly, is mainly for digestive purposes. In it are fer- 

 ments, crystals, food particles (seen in the food vacuoles), oil 

 globules, gas, and pigment granules. 



Flagella and suctorial tubes in protozoa that have them belong 

 to the ectosarc. Skeletal tissues, shells, etc., also belong to this 

 layer. 



The food consists of bacteria, smaller animals, algae, and animal 

 waste. 



Propagation is effected by direct cell division, beginning in the 

 nucleus, by cell budding or by a complicated course of sporulation 

 which may be sexual or asexual. Sometimes division, or budding, 

 occurs rapidly without the segments separating, leading to the 

 formation of protozoa colonies, or swarm spores. 



In the case of the malarial plasmodia, asexual development, 

 (schizogony) takes place in man's blood, while the sexual develop- 

 ment (sporogony) takes place in the mosquito. Protozoa are found 

 in salt and fresh water, in damp places, and in animals as parasites. 



Since the zoological classification has been given and may be used 

 for reference to larger works, the various pathogenic protozoa are 

 given separately without direct reference to their systematic 

 classification. 



There are but two Rhizopods that are parasitic and pathogenic to 

 man. The only one of these of any import is the Amoeba. 



AMCEBA DYSENTERIC OR ENTOMCEBA 

 HISTOLYTICA. 







This is a pear-shaped roundish body from .008 to .05 mm. in 

 diameter. The ectosarc is easily discernible in the pseudopodia, 

 but not in the round quiescent cell. In the endosarc, which is 



