128 



COMPARATIVE ANATOMY 



ment produced by their extension and retraction is called 

 amoeboid movement. 



Careful observation of pseudopodial movement shows us 

 that the formation of a pseudopod is initiated by a slight 

 bulging of the hyaline edge of the cytoplasm ; the bulge 

 increases in size, and for a while the internal granular mass 

 is not affected. Then, rather suddenly, the granular mass 

 seems to flow into the hyaline process ; and, as it flows with an 





*"--/ . !' 



Fig. 28. 



A, A mceba pro feus ; , nucleus; c.v., contractile vacuole; _/, a diatom enclosed in a 

 food vacuole. B, C, D, three successive stages in the division of Atn^ba 

 crystalligera.) showing the amitotic division of the nucleus. E, resting nucleus of 

 Amoeba crystalligera, highly magnified, showing the central so-called nucleolus 

 surrounded by an envelope of chromatin. f, dividing nucleus of the same species, 

 highly magnified. (A after Leidy ; B-F after Schaudinn.) 



active streaming movement of its granules, the hyaline process 

 spreads and extends, the internal granular stream keeping pace 

 with its extension, until a large lobe-like process is formed, as 

 large it may be as the whole of the remaining body of the 



