Figure 4 in Two sea anemones (Cnidaria: Anthozoa: Actiniaria) from the Southern Ocean with evidence of a deep-sea, polar lineage of burrowing sea anemones

Figure 4. Internal anatomy and microanatomy of Chitinactis marmara. A, micro-CT longitudinal scan through whole specimen showing broad, flattened pedal disc, wide oral disc, short actinopharynx and gastrovascular cavity; note cuticle on both pedal disc and column (stained in white); B, longitudinal section through half of distal column showing body layers and strong cuticle; C, longitudinal histological section through half of distal column showing body wall layers; D, detail of histological cross-section through scapulus showing body layers; note thick mesoglea; E, detail of histological cross-section through scapus showing relatively thinner mesoglea and thicker epidermis compared to scapulus; note cuticle attached to epidermis (indicated by arrow); F, histological longitudinal section through column showing strong, longitudinal, circular endodermal musculature with high muscle processes; G, histological longitudinal section through distal column showing mesogleal marginal sphincter musculature; H, histological cross-section through tentacle showing mesogleal longitudinal musculature (indicated by arrow); I, micro-CT cross-section scan through oral disc showing wide oral disc with tentacles; note six rows of columnar tubercles (indicated by arrows) and an introverted tentacle (indicated by asterisk); J, histological cross-section through mid-column showing columnar tubercle; K, histological cross-section through inverted scapulus and scapus showing one cycle of six perfect pairs of mesenteries (numbers 1–6; directives indicated by arrows); second cycle of mesenteries with one missing mesentery of a pair (numbers 7–12; missing mesentery indicated by asterisk), but noticed complete pair on opposite scapulus; L, cross-section dissection through mid-scapus showing three cycles of mesenteries on half of the column (indicated by numbers); M, cross-section dissection through distal column showing arrangement of mesenteries; note introverted tentacle (indicated by asterisk); N, histological cross-section through mid-column showing arrangement of mesenteries; note the unequal development of mesenteries of some pairs (indicated by asterisks); O, detail of a pair of directive pair of mesenteries on distal column; P, detail of a pair of small pair of fourth cycle of mesenteries; note the strong, circumscribed retractor of mesenteries; Q, detail of parietobasilar musculature on a pair of mesentery of first cycle. Abbreviations: ac, actinopharynx; e, epidermis, g, gastrodermis; m, mesoglea; od, oral disc; sc, scapus; sp, scapulus. Scale bars, A, N, 2.5 mm; B, C, 4 mm; D, E, H, O, Q, 0.2 mm, F, 0.6 mm; G, J, 0.5 mm; I, 3, 2 mm; K, L, P, 1 mm; M, 3 mm.