Ultrastructure of seminal vesicle of D. vulgaris (Dash & Viraktamath, 1998) A, B cross-section of seminal vesicle, showing (TE) tunica external, (M) muscle sheath, (EP) epithelium, (N) epithelial cell nucleus, (Sp) sperm, (L) lumen, (ie) intercellular spaces, (TE) the triangular arrowhead indicates tunica external, (BL) the long arrow indicates basal lamina C–E showing (Ma) head of sperm embedded in the homogenous matrix in lumen, (Sp) spermatid, (Sj) the arrow indicates a septate junction, (Mi) microvillus.