Table 1.

Criteria for identification of epithelial stages

Epithelial stages	Description
I-V	Presence of Spg, pachytene Spc, RS, and late condensed elSpt, which are in bundles. Pachytene Spc are relatively small (I-IV) but gradually grow in size toward stage V.
VI-VIII	elSpt are no longer in bundles and start to align (VI) or are aligned (VII-VIII) at the luminal edge of the epithelium, type B Spg or preleptotene Spc on the basement membrane, pachytene Spc large in size.
IX	Start of spermatid elongation, lack of RS, and late condensed elSpt. Late Spc large and early Spc small.
X-XI	Spermatids are elongated but not fully condensed and have a hooked tip, lack of RS. Late Spc very large and early Spc small in size.
XII	Presence of cells undergoing meiotic divisions (metaphase plates) and/or secondary spermatocytes.