Seminiferous tubules, light micrograph. Adjacent seminiferous tubules show different stages of spermatogenesis. The tubule to the left is a more advanced stage with elongated spermatids positioned around the lumen in contrast to the nearby tubule where the elongated spermatids are deeply embedded in the seminiferous epithelium. These differences illustrate both the radial coordination and longitudinal wave of spermatogenesis along the seminiferous tubules. Epoxy resin section, toluidine blue stain. Magnification: x26 when width printed at 10cm.