A principal point of disagreement in conodont ecology between the pelagic depth stratification model and the benthic model of lateral segregation is the mode of life of the conodont animal. A study of the literature on certain Recent benthic and planktic organisms that may serve as ecologic analogues (chaetognaths, isopods, foraminifers) indicates that distributional patterns alone are not definitive of a pelagic versus a benthic habit. Therefore, we doubt that it is possible to determine the major ecologic mode of conodonts solely from distributional data. Because there is not consistent congruence between lithofacies and conodont biofacies, it is unlikely that conodonts were infaunal or sessile epifaunal benthos. The probable alternatives are nektobenthic or neritic pelagic animals and these may have been subject to such similar controlling hydrographic factors that it is now extremely difficult to distinguish between them, especially in an extinct group of uncertain zoologic affinity. Apparently, the only significant line of evidence for pelagic mode is the Occurrence of some conodonts in black shales that are devoid of unquestioned benthic fossils and presumably formed under anoxic bottom conditions.