prismatic layer

prismatic layer

the middle layer of the three layers forming the shell of MOLLUSCS.
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The possibility that these columns are laminae prolongations as in the case of the tertiary prismatic layer of the fibrous shell is controversial.
1970), but "markedly different from the calcite prismatic layer of most other bivalves" (Kennedy et al.
Unionid shells are characterized by an outer periostracum, an intermediate aragonite prismatic layer, and an inner nacreous layer.
The elements in prismatic layer and nacreous layer of Haliotis discus hannai Ino shells were analysed using Energy dispersive spectrometer.
This was coupled with using planar conduction for simulating wall thickness without extruding a prismatic layer and using a discrete ordinates radiation model to account for radiation.
Once the outer prismatic layer has reached full thickness (80-90 [micro]m in Laternula rostrata), a nacreous layer is secreted below (Aller, 1974).
In fact, observations of the prismatic layer showed some significant alterations, presenting fibrous spherulitic crystalline arrangements instead of the nondenticular composite crystals.
Early bivalves built wholly aragonitic shells consisting of an external prismatic layer and middle and inner nacreous layers (Taylor, 1973).
It penetrates the shell mostly without a defined path, crossing the periostracum and the prismatic layer until it reaches the nacreous layer.
The shell consists of the periostracum, prismatic, and nacreous layers with calcite in the outer prismatic layer and aragonite in the inner nacreous layer.
The shells of Mercenaria mercenaria are composed of three distinct shell layers: an outer prismatic layer and a middle and an inner homogeneous layer.