28 



THE PROTOZOA 



Motorium | 



dorsal disc 



Mouth 



Frontal membranellae— 



Contractile vacuole 



Meganucleus' 



Micronucleust 



Cuticl 



Ectoplasm 



Contractile vacuole- 



oral cirri 



oesophagus 



retractor fibres 



Endoderm 



Food vacuoles 



- Caecum 

 - Retractor fibres 



Anus 



Fig. 5. Protozoan structure. — Entodinium. This is a complex 

 ciliate and has much of the differentiation that one expects to 

 find in the higher animals. Thus it has a mouth, gullet, cloaca, 

 myonemes, neuronemes, contractile vacuoles, skeletal system and 

 several nuclei. (After C. V. Sharp.) 



