Abstract
Amended models of meiotic behaviour in tetraploid species' hybrids have been constructed which better reflect the theory and assumptions about chromosome pairing necessary to conduct such analyses. In particular they correct problems concerning the distribution of chiasmata among and within chromosome configurations inherent in the earlier models of Kimber & Alonso (1981). In general these analyses give similar interpretations to the earlier models but in some cases call the previous conclusions into question.