FIGURE 20.27 ■ Smear of human semen illustrating the appearance of mature
               sperm with covering acrosome caps. Stain: hematoxylin and eosin. ×320.
               FIGURE  20.28  ■  Transverse  section  of  a  canine  ductus  deferens  with  the
               surrounding muscle layers and adventitia. Stain: hematoxylin and eosin. ×20.
                                                          834