The time course of male meiosis in the red-backed salamander, Plethodon cinereus.

Tritiated-thymidine autoradiography was used to follow the progress of cells through meiosis in male P. cinereus at 20 degrees C. Spermatocytes spend 7 days in leptotene, 5 days in zygotene and 3 days in pachytene before entering the diffuse stage. Diffuse lasts for 8 days and is followed by a diplotene of 2 days. First and second meiotic metaphase occur a total of 26 days after the end of premeiotic S. Considering the information for P. cinereus together with that for 3 other species, it appears that in amphibians the duration of meiosis does not show the linear relation with C-value that has been described for other groups of organisms.