The scales of modern lungfish.

SUMMARY A description is given of the scales of Epiceratodus, Protopterus and Lepidosiren, and the associated soft tissues. In Epiceratodus the scale still shows considerable differentiation, and its parts can be related in some degree to those of the ancestral cosmoid scale. The cosmine layer has disappeared, but the outer calcified layer probably represents the remains of the lacunar layer, and the inner laminated layer may represent the isopedine. In Protopterus and Lepidosiren the scales are much simplified but their structure can still be understood through that of Epiceratodus. Direct, attachments between the posterior part of the scale and a superficial connective tissue layer are present in all, and the incomplete type of pocket in which the scale lies differs only in detail.