In those subterranean funguses which mature their seeds below the surface of the ground, the lower portion, so soon as this is accomplished in the upper, suddenly takes to grow upwards, carrying along with it the bag, which, on reaching the surface of the ground, bursts its envelopes and scatters its prolific dust to the winds. All funguses, as has already been observed, have in all probability spores, though in a few instances, of byssoid growths, (Hyphas, Himantias, and Æthelias,) these are not apparent; in most cases too, they are attached to an hymenium, into which, or on the surface of which, they are placed till ripe. One very large tribe, by far the largest, are called _Hymenomycetes_, from ὑμήν, a membrane, and μύκος, a fungus; _i. e._ funguses with a seed membrane: to distinguish them from those other kinds, very small numerically in proportion to themselves, _Gasteromycetes_, in which the seeds, arranged and stored away in particular receptacles, named sporanges or thecæ, are with them included in the belly (γαστήρ) of the fungus, as is the case in truffles and puff-balls. The hymenium, like that curiously doubled-down sheet of paper which conjurors turn into so many shapes, assumes a great variety of forms; running down the gills of the mushrooms and the plaits of the _Cantharellus_, up into the tubes of the Boletuses; sheathing the vegetable teeth of _Hydna_, forming an intricate labyrinth of anastomosing plates in _Dædalea_; now rising into little rough eminences on the surface of the _Thelephoræ_, and now affording a smooth investment to that of the _Clavariæ_. It is covered with a veil, which disappears so soon as the spores begin to ripen, and its protection is no longer required; seen under the microscope, it appears to be wholly made up of thecæ. SUCCESSIVE DEVELOPMENT OF THE SPORES.