Fig. 17

Serial block-face SEM images of reproductive structures of Macrostomum schareri. a, b Vagina with a clear muscular sphincter (closed arrowhead in a). c Section through the vagina wall showing dense cilia. d Details of the male system with the male gonopore (closed arrowhead) and the stylet with associated circular musculature (open arrowhead). e Vas deferens filled with sperm. Closed numbered arrowheads indicate mitochondria (1) and two types of vesicles (2, 3) within sperm. The open arrowhead indicates a very narrow region (~ 0.3 μm) of sperm. f Base of the stylet (black arrowhead) showing tissue of the vesicula granulorum with cilia (open arrowhead) penetrating it. The section from (b) is of specimen MTP LS 2714, all others are of MTP LS 2713. Scale bars indicate 10 μm