Guide to the Parasites of Fishes of Canada Part V: Nematoda Author Arai, Hisao P. Author Smith, John W. text Zootaxa 2016 4185 1 1 274 journal article 10.11646/zootaxa.4185.1.1 11620862-ddcf-4c01-b0d9-32867e03d74b 1175-5326 165530 0D054EDD-9CDC-4D16-A8B2-F1EBBDAD6E09 Key to Families of SEURATOIDEA 1 Buccal cavity absent or, if present, derived from cheilostom; cuticle constituting walls of cheilostom having same structure and staining reactions as external body cuticle........................................................ Quimperiidae - Buccal cavity formed from modifications of anterior end of oesophagus (oesophastom); walls of oesophastom surrounded by oesophageal tissue........................................................................... Cucullanidae