The whole of the middle lamella or originally formed cell-wall separating one from another disappears before the adult state is reached, so that the walls of the hydroids consist of a framework of lignified bars, with open communication between the cell cavities.
Ice forms in the night, but disappears with the heat of the sun.
And it grows, merges, disappears from the surface, sinks to the depths, and again emerges.
When a few lumps of sugar are added to a glass of water and stirred, the sugar soon disappears and we are left with a uniform liquid resembling water, except that it is sweet.
In summer at the Bureau Central the intermediate peak nearly disappears in the profound afternoon depression, but it is still recognizable.