As you know the formation of germline cyst as a stage of germ cell development has been reported in Drosophila, Xenopus and some mammals. Now, I'm working with the avian primordial germ cells and I don't know, however they produce germline cyst or not? (related paper: Pepling, M. E., et al. (1999). "Germline cysts: a conserved phase of germ cell development?" Trends Cell Biol 9(7): 257-262)