title: The development and symmetry of the vulval flap of Ostertagia ostertagi.
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases; D005260:Female; D007814:Larva / Q000033:anatomy & histology / Q000254:growth & development; D014251:Trichostrongyloidea / Q000033:anatomy & histology / Q000254:growth & development*; D014252:Trichostrongyloidiasis / Q000662:veterinary; D014844:Vulva / Q000033:anatomy & histology / Q000254:growth & development