Figure 5 in Proboscis sensory cells in Nemertea: comparative morphology and phylogenetic implications

Figure 5. Transmission electron micrographs of proboscis monociliated sensory cells of palaeonemerteans. A, Cephalothrix cf. rufifrons, transverse section of the receptor processes of sensory cells (asterisks). Microvilli reaches the base of the bulblike structure of the cilium (black arrowhead). White arrowheads point to axial rootlets. A high magnification inset shows the filament bundles of the microvillus terminated on axial rootlets. B, Cep. cf. rufifrons, transverse section of the receptor processes of sensory cells. C, Cephalothrix cf. rufifrons, longitudinal section through the globular ciliary tip of a sensory cell. D, Cephalothrix cf. simula, longitudinal section through a group of sensory cells (asterisks). E, Cephalothrix cf. simula, transverse section of the receptor processes with six (black arrowhead) and seven (white arrowheads) microvilli. F, Cephalothrix filiformis sensu Iwata, longitudinal section through a group of sensory cells (asterisks). A high magnification inset on the bottom right shows the septate junction. A high magnification inset on the top right shows a ciliary basal plate (arrowhead) located between the axoneme and centriole. G, Cep. filiformis sensu Iwata, transverse section of the receptor processes with six (black