Goniatites

Goniatites, a genus of fossil cephalopodous mollusca, belonging to the same family as the Ammonites. The genus is characterised by the structure of the septa, which are lobed, but without lateral denticulations, as in Ammonites; they consequently exhibit, in a section, a continuous undulating line. Some forms with slightly waved septa approach very near to the Nautilus. The siphonal portion is shorter than the sides, forming a sinus at the back, as in the Nautilus. The last chamber, the one tenanted by the animal, occupies a whole whorl, and has besides a considerable lateral expansion. The shells are small, seldom exceeding 6 inches in diameter. This genus is confined to the Palæozoic strata: nearly two hundred species have been described from the Devonian, Carboniferous, and Triassic systems.