SPERM MORPHOLOGY AND IMP DISTRIBUTION IN MEMBRANES OF SPERMATOZOA OF CYPRINID FISHES I

Hexagonal (or parallelogrammic) arrays of intramembranous particles (I MPs) have been demonstrated on the head membranes of spermatozoa in th e zebrafish (Kessel er al., 1983) and the rose bitterling (Ohta, 1991) . The present study was designed to examine whether or not the arrays are structures common to spermatozoa of cyprinid fishes from the compa rative spermatology viempoint. The cyprinid fishes investigated belong ed to the four following species: Zacco platypus, Hemigrammocypris ras borella, Zacco temmincki and Pseudoperilampus typus. The distribution of IMPs varied from sparse to dense among different species. Hexagonal arrays of IMPs on the protoplasmic face (PF) and rows of hexagons on the extracellular face (EF) corresponding to the sites of hexagonal ar rays on the PF mere observed. The number of IMPs on the PF was greater than that on the EF in all. four species examined. It was concluded t hat hexagonal arrays of IMPs are present on head membranes of spermato zoa in all cyprinids investigated. This fact supports a possible concl usion that hexagonal (or parallelogrammic) arrays of IMPs are structur es common to spermatozoa of cyprinid fishes.