noun
definition
The integument of the undersurface of the bell, or disk-shaped body, of a jellyfish.
Examples of subumbrella in a Sentence
The umbrella-like body bears a circle of tentacles at the edge, whereby the body can be divided into a convex exumbrella or exumbral surface and a concave subumbrella or subumbral surface.
A medusa has a layer of muscles, more or less strongly developed, running in a circular direction on the surface of the subumbrella, the contractions of which are antagonized by the elasticity of the gelatinous substance of the body.
By the contraction of the subumbral circular muscles the concavity of the subumbrella is increased, and as water is thereby forced out of the subumbral cavity the animal is jerked upwards.
To produce a medusa the actinula grows greatly along a plane at right angles to the vertical axis of the body, whereby the aboral surface of the actinula becomes the exumbrella, and the peristome becomes the subumbrella.