Cell Division in Relation to Reproduction - 45 



PROPHASE 



METAPHASE 



ANAPHASE 



TELOPHASES 



DAUGHTER CELLS 



Fig. 3-4. Mitosis in a typical animal cell (egg cell of a sea urchin). Note particularly the 

 asters, centrioles, and cleavage furrows. These structures are rarely found in plant cells. 



CROSS SECTION 



LONGITUDINAL SECTION 



Fig. 3-5. Paired centrioles of a human tumor cell (Desille lymphosarcoma). Final magnification, X 160,000 

 (approximate). Note the pattern revealed by the cross section: nine triplet groups of tubules (or perhaps fibers) 

 arranged in a circle. This pattern appears to be general, as indicated in electronmicrographs of the centri- 

 oles of various other dividing cells. (Courtesy of Wilhelm Bernhard, Institut de Recherches Scientifiques sur le 

 Cancer, Villejuif, France.) 



