In HA3, spermatogonia (s) are found on the basement membrane. They have round to oval nuclei that are finely granular. When the spermatogonium divides, it forms another spermatogonium and a primary spermatocyte (HA3, p). These cells are easy to identify because their nuclei contain condensing chromosomes. Most primary spermatocytes have moved off the basement membrane toward the lumen. The next cell type in the spermatogenic series is the secondary spermatocyte. This is a brief phase and these cells appear rarely in sections. Moving toward the lumen you will see two additional stages. Early spermatids (e) have small round nuclei, and the more mature late spermatids (l) have the characteristic elongated nuclei of sperm.