Studies of the biology of the lesser weever fish Trachinus vipera Cuvier

The anatomical adaptations to a benthic mode of life are reviewed and discussed. The functioning of the pectoral, pelvic and anal fins in moving sand from underneath the animal, during burrowing, are described. Jets of water directed downwards from the gill chambers, produce a fluid sand-water mixture which facilitates the functioning of the pelvic fins, and the movement of the head into the sand. The direction of water movements associated with gill ventilation, which are propelled almost exclusively by the branchiostegal rays, are outlined. Inhalation is normally through the mouth, which is protected by papillae, from being blocked by sand. When the mouth is covered with sand, the water flow through it is reduced, and some inhalation occurs through the dorsal margin of the operculum, involving use of the supracliethrum.