What is "toxoprion"

Toxoprion lecontei ( Ancient Greek for "bow saw") is an extinct eugeneodont Holocephalid whose fossils are found in marine strata from the Early Carboniferous until the Late Permian. It was one of the many Carboniferous eugeneodonts which bore a palatoquadrate fused to its skull or reduced in other forms, and had its heavily serrated teeth grow outwards on the symphysis of the lower jaw similar to a rounded saw. Despite its jaw showing similarities to another eugeneodont Genus, Helicoprion, the teeth of Toxoprion do not grow into a "whorl", in which smaller and earlier teeth are overlapped with larger teeth grown later in life, to where the jaw resembles the shell of an ammonite. As with other helicoprionids, the Toxoprion jaw instead adds teeth to the terminal end of the jaw and grows in a downward arch, not revolving around preceding teeth.