Fig. 11

Schematic representation of the juvenile three-folded mantle margin in Nodipecten nodosus. a Schematic representation of a cross-section through the animal body, ventral to the top (foot points upwards). b Detail of the region indicated in the inset of a. The curtain-like inner mantle fold is greatly enlarged. The outer fold and the periostracal groove are similar to the postmetamorphic arrangement. The last fold to be formed, the middle one, is provided with numerous tentacles and pallial eyes. Abbreviations: fo, foot; gi, gill; if, inner mantle fold; ma, mantle; mf, middle mantle fold; mm, mantle margin; of, outer mantle fold; pe, periostracum; pg, periostracal groove; sh, shell