Ichthyophthirius multifiliis trophozoite from freshwater fish. This is a section, profiling one cilium which was cut absolutely parallel to the long axis.  The basal body can be clearly seen, as well as the axosome (AX), which is the point at which the central two microtubles of the 9+2 originate. The central microtubules (CMT), outer microtubules (OMT) and ciliary membrane (CM) are also apparent.  Secretory bodies (SB) presumably contain enzymes, released to digest the fish's skin.  80,000x.