112 



BIOLOGY: GENERAL AND MEDICAL 



than one composed of many cells, groups of which can be 

 set aside for special purposes. 



Composite structure, however, does not necessarily 

 imply complicated structure; it only affords opportunity 



FIG. 35. Various forms of Radiolaria. (After Haeckd.) 

 1, Ethmosphrera siphomophora; 2, Actinomma inerme; 3, Acanthometra 

 xiphicantha; 4, Arachnosphcera oligacantha; 5, Cladococcus viminalis. 



for it. Thus we find lowly forms of life sometimes made 

 up of congeries of similar cells whose cytoplasm has 

 become united into a general undifferentiated mass or 

 plasmodium. Such formations occur in both the animal 



