Tube ultrastructure of fossil Ditrupa (Serpulidae)
Ditrupa strangulata, cross section, showing internal calcitic
homogeneous granular layer (left) and external calcitic
irregular prismatic layer. Eocene,
Ditrupa gracillima, longitudinal
section, showing external calcitic irregular
prismatic layer. Middle
Ditrupa gracillima, longitudinal section, showing details of the external calcitic irregular prismatic layer. Middle Miocene, Australia.
SEM photographs by
O. Vinn