Données paléobiologiques et paléobiogéographiques sur quelques Strophochonetinae du Dévonien d'Espagne et du Massif Armoricain

The lack of hinge spines on the left side of the ventral valve in Chonetacea is demonstrated here for the first time. This morphological peculiarity has a special bearing on the evolutionary trends of the Strophochonetinae. The existence of several species of Chonetacea, both in the Armorican Massif, the Cantabrian Mountains, and Aragon, is a new fact which confirms very close relations between these three areas during Lower Devonian times.