The lampbrush phase of 6 F1female hybrids ofTriturus cristatus carnifex♀ ×T. vulgaris meridionalis♂ and 1 female hybrid of the reciprocal cross was analyzed in several growing oocytes. The chromosome constitution of these hybrids was found to be diploid and derived from a regular, although heterospecific amphimixis (2n= n♀ + n♂). All the oocytes contained 24 unpaired lampbrush chromosomes, among which the single univalents of the 2 parental sets were recognized by their cytogenetic markers (loops, spheres, NORs, other objects and lateral projections). Lampbrush univalents can be joined to one another by transitional fusions of spheres and telomeres and, occasionally, by very rare chiasmata which may be defined as anomalous since they form between heterologous chromosomes and probably represent a further impediment to subsequent meiotic stages. Problems concerning chromosomal homologies and cytogenetic aspects of sexuality and sex determination in these species hybrids have been discussed in the light of the present findings.