Spermatozoa of Conger myriaster observed by electron microscopy

We examined the morphological features of spermatozoa from Conger myriaster by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Spermatozoa consisted of three regions, a head, neck and flagellum. Total length was approximately 40 mu m, with the head 3 mu m, neck 0.5 mu m and flagellum about 37 mu m. The head was crescent-shaped, with a mitocho ndrion on the concave surface. The neck, with an attached rootlet, consiste d of two constrictions close to the base of the flagellum. Two bundles exte nding from the proximal centrioles existed on both the convex and concave s urfaces of the sperm head. The flagellum showed a 9+0 axonemal pattern. Som e flagella showed a coiled form, the developmental mechanism of which was u nclear. These features were compared with those of other Anguilliformes.