Our chromosomal sample of 28 April 2011 from the Inn River (cytoform ‘A’) had 3 larvae with dark gill histoblasts of which 1 larva had 11 filaments and 2 larvae had 12 filaments; the 24 October sample had 6 larvae with dark gill histoblasts of which 4 had 10 filaments and 2 had 12 filaments.