Conodonts

Conodonts, minute fossils met with in Palæozoic strata. They are variable in form, and look very like the teeth of different kinds of fishes, some being simple slender pointed sharp-edged cones, while others are more complex, resembling in form the teeth of certain sharks. Their affinities are very uncertain—some maintaining that they are really the minute teeth of fishes allied to the living hag-fishes and lampreys—others suggesting that they have more analogy with the hooklets or denticles of annelids and naked molluscs.