Fig. 2. Spermiogenesis in Corydoradinae. a-d) Corydoras flaveolus; e-h) Corydoras aeneus; i) Scleromystax lacerdai. a) Spermatids together with spermatozoa in the lumen of the testicular tubules. b-d) Early spermatids connected to the Sertoli cells surface. e and e-insets) Arrangement of the centriolar complex showing electron-dense material between centrioles, and flagellum with classical (9+2) axoneme. f to h) Midpiece showing mitochondria, vesicles, and electron-dense circular structure (longitudinal sections). i) Late spermatid. (a) X 3250; (b) X 4875; (c, d) X 5750; (e) X 13250; (e-inset left, i) X 17000; (e-inset right) X 25850; (f, g) X 9750; (h) X 7750. C: centriolar complex; D: distal centriole; L: lumen; N: nucleus; P: proximal centriole; S: Sertoli cell; V: vesicles; Z: spermatozoon; Asterisk: mitochondria, Arrow: cytoplasmic channel; Arrowhead: point connection; Double arrowhead: electron-dense material between the centrioles; Lozenge: electron-dense circular structure.