Abstract
Cell culture of spermatogenic cells from the primary spermatocyte stage to the early, midspermatid stage has been established for the Japanese newt, Cynops pyrrhogaster (1–4, 10, 11) and for Xenopus laevis (2, 3, 5, 17, 18). The results of many investigations suggest that sperm maturation in vitro for each species proceeds along the same pathway and under the same temporal control as in vivo. Since the shape and size of mature sperm of these two species are very different, comparative studies would enable us to elucidate the mechanisms by which sperm morphology is determined. The results obtained from in vitro studies of spermatogenesis in Cynops and Xenopus demonstrate that there are common and species-specific features.