Fig. 8
Histology of the testis of the male brown bullhead (Ameiurus nebulosus) inhabiting the oxbow lake of the Vistula River, Poland. A: testis in late maturation class; the entire lumen of the tubule was filled with early spermatids not enclosed in cysts (asterisk). A few reserved spermatogonia A were located on the high tubule wall (arrow), September. B: testis in the late maturation class; lumen tubules filled with spermatids, and a few cells have completed spermiogenesis, forming spermatozoa (asterisk), November. C: testis in the late maturation class at spawning; tubules filled with spermatids (white asterisk), and some tubules were empty (black asterisk). Spermatozoa may not be present in the cross-section of tubules during the spawning period May; D: the mid-maturation stage of the testis during the post-spawning period, the periphery of the tubules contains cysts with proliferating spermatogonia B and primary spermatocytes (arrow). The tubule lumen is filled with older spermatogenic cells exfoliating from cysts (asterisk). Usually, the cyst has a small number of cells. July. Scale bar: 50 μm. A, B, D: Heidenhain’s iron hematoxylin staining. C: Alcian blue with PAS staining.
