title: Invertebrate spermatozoa--structure and spermatogenesis.
mesh_terms: D000177:Acrosome / Q000648:ultrastructure; D000818:Animals; D002467:Cell Nucleus / Q000648:ultrastructure; D003593:Cytoplasm / Q000648:ultrastructure; D007448:Invertebrates / Q000033:anatomy & histology*; D008297:Male; D008854:Microscopy, Electron; D008928:Mitochondria / Q000648:ultrastructure; D013091:Spermatogenesis; D013094:Spermatozoa / Q000648:ultrastructure*