INTRODUCTION TO PROTOZOOLOGY 3 



MORPHOLOGY. 



It may be that all protozoa have not yet been recognized, but some 

 of those known are large, e.g., the Sarcocystid^e in muscle; and some 

 are small, e.g., the Ikemoprotozoa. 



The protoplasm consists of — 



A clear hyaline ectoplasm ; 



A dark granular endoplasm. 



The protoplasm contains — 



One or more nuclei, a complex body of chromatin and achromatic 

 substance. It may be single or divided into two — 



One controlling the function of nutrition — trophonucleus ; 



One controlling the function of motion — kinetonucleus, or 



A macronucleus which is trophic and kinetic ; and 



A micronucleus Avhich is purely reproductive. 



Chromidiosomes are smaller particles of chromatin which give rise 

 to the chromidia, intra- or extra-nuclear. 



Metachromniic granules consist of chromatic grains in process of 

 ana- or kata-bolism. 



Volutine granules contain nucleic acid and food material for the 

 nucleus. 



Metaplasmic granules are products of cytoplastic ana- or kata- 

 bolism. 



Centrosomes, one or two granules outside the nucleus essentially 

 concerned in binary fission. 



Archoplasm, the clear protoplasm around the centrosome. 



Rhizoplast, that portion of the flagellum which penetrates into the 

 cytoplasm. 



Vacuoli, their function may be — 



Respiratory and excretory ; 



Digestive and excretory. 



Protozoa move by pseudopodia, cilia, or flagella, or they may 

 become quiescent and encysted. 



LIFE-HISTORY. 



Under favourable conditions of food, moisture, temperature, &c., 

 reproduction is asexual and may follow the methods of — 



(i) Binary fission. 



This is single division of the nucleus into two portions, followed 

 by the cytoplasm. 



(2) Gemmation. 



The nucleus divides into two or more portions, Avhich separate at 

 the periphery, each being surrounded by a differentiated portion of 

 the cytoplasm. 



