Examples from the Web for pneumatocyst
It has however no communication with the enclosed cavity of the pneumatocyst.
The structure so formed is the rudiment of the pneumatocyst (ep).
Rhizophysa filiformis, pink, with deep red patch surrounding the aperture of the pneumatocyst.Colouration in Animals and Plants|Alfred Tylor
In the next stage the air-cavity of the pneumatocyst becomes established within the epiblast.