Les relations isopedine - tissu osseux dans le post-temporal et les ecailJes de la ligne laterale de Latimeria chalumnae (Smith)

The scaly part of the posttemporal bone and the lateral-line scales have the same structure as other scales. However, the lateral line with its bony canal induces some local transformations in both structures. The posttemporal bone can be interpreted as a lateral-line scale whose "dermo"-component is extensively developed. With its composite structure, both osseous and scaly, the posttemporal bone affords an instance peculiarly well suited for studying the relationships between isopedine and bone. The observations demonstrate that isopedine whose superposed collagen layers make a double-twisted plywood, is a specialized structure which evolved from a bony tissue. The fibrous basal plate of a Latimeria scale is homologous to the osseous basal plate of a cosmoid scale.