140 



BIOLOGY OF THE PROTOZOA 



2. Pseudopodia.^ Pseudopodia are more or less temporary pro- 

 jections of the cortex which may serve for purposes of locomotion 

 or, more often, as food-trapping or food-catching organoids. Four 

 types are recognized, axopodia, rhizopodia (myxopodia), filopodia, 

 and lobopodia, which differ widely in their structural make-up. 





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Fig. 7.3. — Types of pseudopodia. A, B, Eruptive type of lobopodium; C, myxo- 

 podia type of Foraminifera; D, axopodia type of Heliozoa. (After Calkins.) 



Of these only the first type can be regarded in a strict sense as 

 motile organs (see p. 133), the others functioning as food-catching 

 organoids, or mere protrusions of the semifluid body. 



Axopodia.— Axopodia are different from other types of pseudo- 

 podia in possessing, like flagella, central axial fibers of specialized 

 protoplasm derived from endoplasmic kinetic elements. They are 



