Spermatogenic cycle, sperm storage, and Sertoli cell size in a scolecophidian (Ramphotyphlops nigrescens) from Australia

Spermatogenesis in the southern Australian blindsnake Ramphotyphlops nigres cens is seasonal, with sperm production peaking in autumn, reduced in sprin g, and testicular recrudescence occurring from late spring to summer. Sperm is present in the epididymides from autumn to early summer. The retrocloac al sacs in this species do not function as sperm storage organs, contradict ing the only previous hypothesis on the function of these structures. A pec uliar feature of the testes of this species is the large size of the Sertol i cell nuclei, which are much larger than the spermatogenic cells.