Plastron
From Free net encyclopedia
The plastron is the nearly flat part of the shell structure of a tortoise, what one would call the belly, similar in composition to the carapace; with an external layer of horny material divided into plates called scutes and an underlying layer of interlocking bones.
In certain families there is a hinge between the pectoral and abdominal scutes allowing the turtle to almost completely enclose itself. In certain species the sex of a testudine can be told by whether the plastron is concave, male or convex, female. This is because of the mating position.
Turtle plastrons were used by the ancient Chinese in a type of divination called "plastromancy" (from 'plastron' + 'pyromancy'). See also oracle bones.
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See also
- "Plastron" is also the name of a half-jacket used in the sport of Fencing.
- "Plastron" is also the name of the bulge on an aircraft, such as the Airbus A340, under the fuselage between the wings that is used to correct airflow around the engine pylons.
- A "plastron" is also a thin permanent layer of air around the body of some aquatic insects and held in place by hydrophobic hairs.bg:Пластрон