| Abstract: | The microstructure of two species of Cladochonusfrom Algerian Carboniferous, C. crassus (McCoy) and C. cf. tenuicollisMcCoy, has been studied by ultra-thin sections. Their walls consist of: 1. an external fibrous layer, 2. a median layer of undulating lamellae, 3. an internal zone of slender, elongated elements to which the name of «grundulae is given here. New data bring complements to the generic diagnosis of Cladochonus s. str. Some Permian cladochonid forms show different microstructures and should, therefore, be shifted to new generic units. |
