Evidence on the nature of conodonts

Study of conodont assemblages from strata of McLeansboro, Pennsylvanian, age near La Salle, Illinois, shows that typically a pair of polygnathids, a pair of bryantodids, and several pairs of hindeodellids are present. A rarer type of assemblage is characterized by forms strikingly different in character. From the biological viewpoint it is believed that two taxonomic divisions of the group are represented by these two kinds of assemblages. The zoological relationship of the conodonts with the Paleozoic Annelida is favored. This study and several previous ones show that conodonts which have been previously referred to different families may be parts of a single individual. It is advocated that the present nomenclature be removed to the Ordo Militaris or utilitarian classification proposed by Croneis and that, as far as possible, a biological classification based on phyletic relationships of the assemblages be substituted.