The argonaut constructs its shell via physical self-organization and coordinated cell sensorial activity. (A. Checa et al.)_Dataset.

The shell of the cephalopod Argonauta consists of two layers of fibers that elongate
perpendicular to the shell surfaces. Fibers have a calcitic core sheathed by extremely
thin organic membranes, which form a polygonal network in cross-section. During
growth, fibers with small cross-sectional areas tend to shrink, whereas those with large
sections tend to widen, i.e. they follow the von Neumann-Mullins law. We hypothesize
that fibers evolve as an emulsion between the fluid precursors of both the mineral and
organic phases. In addition, when polygons reach big cross-sectional areas, they
become subdivided by new membranes. To interpret this partitioning process we infer
that the living cells from the mineralizing tissue are able to ‘locate’ and subdivide
particularly large polygons. To do this, living cells must perform contact recognition and
subsequent secretion at sub-micron scale. Accordingly, the fabrication of the argonaut
shell proceeds by physical self-organization together with direct cellular activity