Figure 7 in Morphological perspective on the classification and evolution of Recent Pterioidea (Mollusca: Bivalvia)

Figure 7. Mantle edge morphology in the Pterioidea. Histological cross-section (5 µm, Alcian Blue/Periodic Acid/Schiff's trichrome stain). A, three-fold condition: Pinctada mazatlanica (AMNH 311790, 107.6 mm; scale bar = 1 mm); B, four-fold condition: Isognomon radiatus (AMNH 298944, 29.3 mm height; scale bar = 0.1 mm); C, Pteria colymbus (AMNH 298920, 63.6 mm; scale bar = 0.1 mm). Inset (B), close up of the distal extremity of the OF-1 fold (boxed) showing the ocellus (scale bar = 0.02 mm). The right panel of (C) shows two close ups of the distal extremity of the OF-1 fold (boxed) at different focal planes (scale bar = 0.03 mm). Abbreviations: c, circumpallial artery; ec, eosinophilic cells [putative photoreceptors sensu Morton (2001)]; if, inner mantle fold; n, circumpallial pallial nerve; o, ocellus; of, outer fold; p, periostracum; pm, pallial muscle; t, tentacle.