Fig. 8 in The ultrastructure and building of graptolite dissepiments

Fig. 8. Dendroid graptolite "Dictyonema" sp. 2. Ordovician boulder No. O.62, TEM micrographs of fuselli as components of a dissepiment. A. Fusellus with head and trunk normally developed, note that lateral limbs of adjacent fuselli merge to produce condensed layers of dependent cortex (arrow). B. Fuselli with reduced trunk resembling microfuselli. C. Ultrastructural details of fusellar and cortical fabric within a fusellus. D. Cortical and fusellar material within a dissepiment.