Nancy Hartshorne Kirk

• More thoughts on bithecae, budding and branching in the Graptolithina
• More thoughts on the construction and functioning of the rhabdosome in the Graptoloidea in the light of their ultrastructure
• Some thoughts on convergence and divergence in the Graptolithina
• Some thoughts on the construction and functioning of the rhabdosome in the Retiolitidae
• Some thoughts on the construction of the rhabdosome in the Dendroidea, in the light of the ultrastructure of the Dendroidea and of Mastigograptus
• Some thoughts on the construction of the rhabdosome in the Graptolithina