OBSERVATION OF ANCYROCEPHALUS MOGURNDAE(MONOGENEA;ANCYROCEPHALIDAE)FROM THE GILLS OF THE MANDARIN FISH, SINIPERCA CHUATSI BY SCANNING ELECTRON MICROSCOPY

The surface of the head organ of the adult monogenean Ancyrocephalus mogurndae(Gussev)is covered with numerous pit-like invaginations. The anterior adhesive apparatus is composed of 3 pairs of adhesive sacs, situated on the distal extremities of the head lobes of the head organ(each middle head lobe with 2 adhesive sacs; each lateral head lobe with 1 adhesive sac). The buccal cavity is on the middle line of ventral surface, close to the lower limit of the head organ. The genital atrium opens beneath the oral area, whereas the vaginal pore opens on the dorso-lateral surface of the anterior region, and the microvillus-like projections are concentrated around the vaginal pore. The copulatory organ is situated on the lower left of the genital atrium, including copulatory tube with wavy surface and supporting apparatus with wan-like outgrowth on its surface. The haptor possesses 2 pairs of anchors, each with a groove on the surface, together with 7 pairs of marginal booklets with the tapering blade turning round its base. Presumed sensory endings are of at least two types:(1)Uniciliated structure, projecting from a pit or supported by a collar of tegument, which are distributed sparsely over the general body surface; and(2)Retractable papilla, lying outside the adhesive sac of lateral head lobe, which seems to be a compound sense organ not previously encountered in other monogeneans. Trichodinids hyperparasitism can be observed on the surface of some A. mogurndae.