ULTRASTRUCTURE OF THE SPERMATOZOON OF HYMENOLEPIS-STRAMINEA (CYCLOPHYLLIDEA, HYMENOLEPIDIDAE), INTESTINAL PARASITE OF ARVICANTHIS NILOTICUS(RODENTIA) IN SENEGAL

The mature H. straminea spermatozoon is filiform and lacks mitochondri a. It exhibits an apical cone of electron-dense material and eight hel icoidal crest-like bodies 50-100 nm in thickness. The cortical microtu bules are spiralized and make an angle of about 30 degrees to the sper matozoon axis. The axoneme, of the 9 + ''1'' pattern of the Platyhelmi nthes, does not reach the extremities of the spermatozoon. The nucleus is a compact cord wound in a spiral around the axoneme. Depending on the level of section it appears annular or crescent-shaped. The cytopl asm exhibits many electron-dense granules in regions III, IV and V of the gamete. A nucleus with both annular and crescent-shaped sections h as never been described in a species of the Hymenolepididae. In additi on we report for the first time the existence of eight crest-like bodi es of different length in the cestodes.