title: Observations on the germ cell ultrastructure of male diploid and tetraploid Odontophrynus americanus (Amphibia: anura).
mesh_terms: D000818:Animals; D001001:Anura / Q000033:anatomy & histology*; D005854:Germ Cells / Q000648:ultrastructure*; D008297:Male; D008854:Microscopy, Electron; D013091:Spermatogenesis