_Phallus impudicus_ (Stink-horn) (Fig. 179), has a fruit-body which at first is white, heavy, and soft, and resembles a hen’s egg in shape and size. The peridium is divided into three layers (Fig. 179 _e_, _g_, _f_) of which the external and internal are membranous, and the middle one very thick and gelatinous; each of these has again a laminated structure. The peridium when ruptured remains as a sheath (_k_) at the base of the stalk. The receptacle at first is strongly compressed (_h_) but afterwards expands into a long stalk (_l_) which bears the conical gleba (_m_). Prior to the rupture of the peridium the gleba consists of a greenish mass (_i_) which, when exposed, emits a carrion-like stench serving to attract flies, by whose agency the spores are distributed. It is found commonly in hedgerows and in woods, growing on the ground. The much smaller and less common _P. caninus_ is found on rotten tree-stumps.--In _Clathrus cancellatus_ the receptacle expands into a bright red, reticulate structure. A native of the South of Europe. _Colus_, _Aseroë_, _Mitromyces_. Order 2. =Sphærobolaceæ.= An intermediate layer of the _peridium_ swells when ripe, becomes convex, and _ejects the remaining_ spherical _portion of the fruit-body_ which contains the spores. _Sphærobolus carpobolus_ has small, spherical fruit-bodies which open in the form of a star. [Illustration: FIG. 179.--_Phallus impudicus_ (Stink-horn), somewhat diminished. Fruit-bodies in all stages of development (_b_, _c_, _d_ and _k-m_) are seen arising from a root-like mycelium (_a_); _d_ longitudinal sections through a fruit-body before the covering has ruptured.] Family 4. =Gasteromycetes.= The fruit-body is _angiocarpic_, fleshy at first, and later generally more or less _hard_ and _continues closed after the_ spores _are ripe_. The tissue lying immediately inside the _peridium_ is termed the _gleba_; it is porous, containing a larger or smaller number of chambers lined with the hymenium, which is either a continuous layer of basidia or else it fills up the entire cavity. The basidia as a rule bear four spores, sometimes eight (_Geaster_), or two (_Hymenogaster_). The tissue of the walls (_trama_) consists often (_Lycoperdaceæ_) of two kinds of hyphæ, some thin and rich in protoplasm, divided by transverse septa and bearing the basidia; others thicker and thick-walled which do not dissolve like the former on the ripening of the spores, but continue to grow and form a woolly, elastic mass, the _capillitium_, which may be regarded as highly developed paraphyses. The peridium may be either single or double, and presents many variations in its structure and dehiscence. The mycelium is generally a number of string-like strands, living in soils rich in humus.