Zooecia either arising from a stolon, without lateral connexion with one another, or laterally united to form sheets.
In the first place, buds may be produced only from the hydrorhiza, which grows out and branches to form a basal stolon, typically net-like, spreading over the substratum to which the founderpolyp attached itself.
From the stolon the daughter-polyps grow up vertically.
Buds may be produced from the manubrium, radial canals, ring-canal, or tentaclebases, or from an aboral stolon (Narcomedusae).
A " stolon " of unknown origin produces thirty-two buds, which become as many Polypodia; each has twenty-four tentacles and divides by fission repeated twice into four individuals, each with six tentacles.
Obelia forms numerous polyserial stems of the characteristic zigzag pattern growing up from a creeping basal stolon, and buds the medusa of the same name.
In some cases the buds do not become detached at once, but the stolon continues to grow and to produce more buds, forming a " bud-spike " (Knospencihre), which consists of the axial stolon bearing medusa-buds in all stages of development.
The coenosarc may consist of a single elongated tube or stolon, forming the stem or axis of the cormus on which, usually, the appendages are arranged in groups termed cormidia; or it may take the form of a compact mass of ramifying, anastomosing tubes, in which case the cormus as a whole has a compact form and cormidia are not distinguishable.
Woltereck considers the siphonophores most nearly allied to the Narcomedusae, producing like the buds from an aboral stolon, the first bud being represented by the pneumatophore or protocodon, in different cases.
Thus the umbrella of the Siphonula became the protocodon, and its manubrium, the axis or stolon, which, by a process of dislocation of Organs, escaped, as it were, from the sub-umbrella through a cleft and became secondarily attached to the ex-umbrella.
B, Longitudinal lobe or stolon of the coxal gland.
- Part of a branch of Bowerbankia pustulosa, showing the thread-like stolon from which arise young and mature zooecia.
- Part of the creeping stolon, with zooids, of Pedicellina belgica.
In other Entoprocta the buds on a horseshoe retain a high degree of individuality, a shaped l o p h o - thread-like stolon giving off the cylindrical phore; stalks, each of which dilates at its end i, Ectocyst; into the body of a zooid.
Ctenostomata the colony is similarly constituted, a branched stolon giving off the zooids, which are not connected with one another.
In the majority of Ectoprocta there is no stolon, the zooids growing out of one another and being usually apposed so as to form continuous sheets or branches.
Such outgrowths are called stolons, and a stolon may be simple, i.e.
St, Stolon; p ?
Formerly all corals in which tabulae are present were classed together as Tabulata, but Tubipora is an undoubted Alcyonarian with a lamellar stolon, and the structure of the fossil genus Syringopora, which has vertical corallites united by horizontal solenia, clearly shows its affinity to Tubipora.
Medusae often have the power of budding, and the buds are formed either on the manubrium, or at the margin of the umbrella, or on an outgrowth or "stolon" produced from the exumbral surface.