350 



MARGARET R. LEWIS AND WARREN H. LEWIS 



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Fig. 4 A, b, c, d, e, cells from a 2-day culture of heart from a 5-day chick. 

 a, cell with 69 mitochondria of granular type, somewhat radially arranged about 

 the central body, b, cell with 125 mitochondria of very different shapes and sizes, 

 about the central body and scattered through the cytoplasm, c, cell with 37 

 mitochondria about the central body, mostly granular in type; X 1080 diam. 

 d, cell with about 90 mitochondria about nucleus and central body, mostly rod- 

 and thread-shaped; X 540 diam. e, group of six adjoining cells; as in a the cells 

 with granular and short, rod-shaped mitochondria show the latter arranged about 

 the nucleus and central body; one cell contains 40 and the other 54 mitochondria 

 of the short and long rod- and thread-shaped types, which are arranged more 



