Albertiana Research Article
Abstract-Comparative-morphological analysis of hard rounded and rhomb- and trapezoid-like structures from the Lower Triassic deposits of South Primorye and the Polar Urals of Russia as well as from the Upper Ordovician of South Africa, from the Silurian of North America, and from the Lower Carboniferous of Scotland showed that they are located in the head part of euconodont animals in front of the tooth apparatuses symmetrically to its sagital axis. It is suggested that a pair of such attaching H elements with the help of muscles connected the isolated tooth elements and governed them in the working process. All skeletal and tooth elements and their connective tissues were in the rounded food sac localized on the outer ventral side of the animal. In the process of the food sac functioning, probably, the food particles in it were filtered from water, which was removed through special holes, and then a food clot was formed and migrated into the food channel (gut). Some groups of the euconodont animals were, perhaps, swimming filtrators and dwelled in the benthic water layer.