Abstract

As a series of systematic classification of paramphistomes, the worms in the rumen and reticulum of 310 Korean cattle slaughtered at Chonju abattoir were collected from February 1986 to June 1987 and were classified by morphology of the worms. Afterwards, the karyotype of Fischoederius cobboldi (Poirier, 1883), which is a very rare species in Korean cattle, was studied with germ cells of the worm by means of modified air-drying method. The chromosome numbers in the haploid and diploid cells of 315 F. cobboldi were n=9 and 2n=18, respectively. The meiotic divisions were observed frequently; 1,904 haploid and 49 diploid cells were recognized. Nine pairs of mitotic chromosomes were homologous in the metaphase stage and the chromosomes were composed of seven medium-sized metacentrics (m) or submetacentrics (sm) and two small-sized submetacentrics (sm). While, meiotic metaphases were composed of seven medium and two small-sized chromosomes. The 3rd, 4th, 2nd and 5th pairs of chromosomes was metacentric having centromere indices of 40.4 per cent, 40.0 per cent, 39.7 per cent and 38.9 per cent, respectively, and the remaining ones were submetacentric with centromere indices from 32.4 per cent to 36.2 per cent. As a series of C-banding method, C-band was shown in centromeric region from all of the haploid germ cells, except chromosome No. l which included heterochromatin at the tip region. Chromosomes No. 4, 6 and 8 showed remarkable C-band distinguished from others.