Meiotic divisions of spermatocytes of Acanthocephalus anguillae stained with Giemsa. A Zygotene. B Pachytene. C Early diplotene with three chiasmata in the longest bivalent (arrows), representing the largest chromosome pair No. 1. D Late diplotene, two cells. E Metaphase I bivalents, more cells. F Late metaphase II. G Pachytene nucleus with one B chromosome (ZŠ population). H Diplotene nucleus with one B chromosome (ZŠ population). Asterisks indicate the X chromosome; arrowheads in G, H indicate the B chromosome. Bar = 10 μm.