For this reason, they act like surfactants, reducing the surface tension of saliva, and forming a homogeneous film on all oral surfaces.
12.
Each septum is extended into a septal funnel that opens onto the oral surface and facilitates the flow of fluid into and out of the animal.
13.
These are elongate, fleshy tendrils set along the sides of the oral surface of the arms, the longest being in the mid-arm region.
14.
The entocodon is the "'primordium "'( i . e . the first cells that give rise to the development of an organ ) of the "'subumbrella "'( i . e . the concave oral surface of a medusa ) in the development of medusae from the gonophore.
15.
Despite the battery of sharp spines on the aboral surface and blunt spines on the oral surface, the crown-of-thorns starfish's general body surface is membranous and soft . When the starfish is removed from the water, the body surface ruptures and the body fluid leaks out, so the body collapses and flattens.
