No. 2 Part of an intermitotic fibroblast of Xenopiis laeiis in culture 

 photographed at intervals to show mitochondrial movement, in particular 

 of the mitochondrium indicated. X I200 (reduction 7/10). Culture by- 

 Miss M. M'E. Preston. 



b 63 seconds after o 



c 38 ,, „ d 



d 120 ,, ,, c 



e 60 ,, „ d 



f 106 seconds after e 



g 31 „ r. f 



h 350 » M g 



'■ 6 „ „ h 



