34 THE STEUCTUEAL UNITS OF LIVING MATTEE 



sistency of the white of an egg. This hquid itself is 

 colorless, but while it appears clear at the edges, its inner 

 part is filled with tiny granules that give it a slightly 

 grayish tinge. The clear outer part is called ectoplasm 

 to distinguish it from the granular portion or endoplasm. 

 These terms also {ecto, meaning outer; endo, meaning 

 inner) serve to indicate the position of the two forms. 



Fig. 10 — Araceta (Amaba proteus) ; », food vacuole ; c, contractile vacuole ; ec, 

 ectoplasm; ert, endoplasm; v, water vacuoles ; n, nucleus. 



The endoplasm is seen also to contain many round bubble- 

 like bodies (vacuoles) which are filled, some with water, 

 some with small particles of food. Besides these we note 

 a single dark body (nucleus) in which is a smaller dark 

 spot (nucleolus). This nucleus is actually only another 

 form of protoplasm, and the ectoplasm and endoplasm 

 together are spoken of as cji^oplasm to distinguish the 

 nucleus from the liquid parts. In structure this tiny 



