AbstractThe scanning electron microscope was used to examine the Sertoli cells in normal and germ‐cell‐depleted testes. The Sertoli cells appear to attain characteristic configurations in the various stages of the cycle of the seminiferous epithelium. In tubules containing maturation‐phase spermatids, Stages I‐IV, the Sertoli cells exhibit column‐like bases which give rise to lamellae measuring 25–30 μm in width which ensheath the spermatids and residual cytoplasmic bodies. In the Stages VIII‐IX long flat sheets of Sertoli cytoplasm rest atop the step‐8 and ‐9 spermatids. These sheets are oriented parallel to the basement membrane of the tubule with their long axis parallel to the long axis of the tubule. In Stages V‐VI the head and proximal portion of the tail of the maturation‐phase spermatids are ensheathed in sleeve‐like Sertoli cell processes. Cuff‐like terminations demarcate the terminus of these sleeves that surround maturing spermatids up to spermiation. In tubules undergoing spermiation, the sleeves retract so that only the tip of the spermatid head remains in the sleeve. Appendicular processes extend from the dorsum of the Sertoli cell sleeves in the tubules undergoing spermiation. After spermiation the appendix elongates while the sleeve evaginates until the everted sleeve is a finger‐like process that extends into the tubular lumen. In tubules in which the seminiferous epithelium has been depleted with epinephrine injections the Sertoli cells attain two configurations. The first is characterized by having long attenuated lamellar processes that orient perpendicular to the basement membrane, with numerous ramifying processes arising from the lamellae. In the second configuration the Sertoli cells' lamellae orient parallel to the basement membrane of the tubule and lack the elaborate ramifications see