Hydrozoa - Wikipedia
In any given colony, the majority of polyps are specialized for feeding. These have a more or less cylindrical body with a terminal mouth on a raised protuberance called the hypostome, surrounded by a number of tentacles. The polyp contains a central …
Hydroids: Hydrozoa - Encyclopedia.com
Hydroids (HIGH-droyds) have two body forms. One is the medusa (mi-DOO-suh), a jelly-like, umbrella-shaped, freely swimming form with a mouth and tentacles that face down. The other is a colony of polyps (PAH-luhps), or tube-shaped sacs that have a mouth and tentacles that face up. The polyp form is fixed to the material on which it lives.
Hydroid | Characteristics & Life Cycle | Britannica
Hydroids have three basic life-cycle stages: (1) a tiny free-swimming ciliated planula larva about 1 mm (0.04 inch) long, which settles and metamorphoses into (2) a sessile (attached), usually colonial polyp stage, which in turn liberates (3) a gamete-producing male or …
Hydrozoa (Hydroids) - Encyclopedia.com
Hydroids can be solitary, but generally form modular colonies by simple budding. Polyps can be specialized for different functions (defensive dactylozooids, reproductive gonozooids, nutritive gastrozooids, etc.). Polyps give rise, by asexual budding, to planktonic, free-swimming, and solitary hydromedusae, representing the sexual adult.
Obelia Hydroid : First Generation - National MagLab
2015年11月13日 · One generation, illustrated in the photomicrograph above, lives in hydroid colonies, consisting of polyps. The polyps are stalklike forms that attach to a surface (usually the ocean bottom) by means of root-like filaments. The polyps reproduce asexually, by budding, and create new polyps until it has formed a treelike colony.
Hydroids (Cnidaria, Hydrozoa): A Neglected Component of Animal …
Small polyp colonies (usually less than 1 cm high) are reptant and tend either to grow on other organisms or to form “meadows,” growing directly on primary substrates where they can play a certain ecological role in becoming habitats for other species. Small hydroids are mostly overlooked, being considered as mere epizoites.
Hydroids: Hydrozoa - Physical Characteristics - Polyps, Type, …
Hydroids (HIGH-droyds) have two body forms. One is the medusa (mi-DOO-suh), a jelly-like, umbrella-shaped, freely swimming form with a mouth and tentacles that face down. The other is a colony of polyps (PAH-luhps), or tube-shaped sacs that have a mouth and tentacles that face up. The polyp form is fixed to the material on which it lives.
Changes in the patterning of a hydroid colony - ScienceDirect
2006年8月16日 · Changes in the set of polymorphic zooids in colonial hydroids (Cnidaria, Hydroidomedusae) are another example of possible alteration of patterning during animal ontogenesis. The hydroid colony can be imagined as a system of branched tubes composed of two tissue layers: outer ectoderm and inner endoderm (gastroderm).
Aquascope|Facts|Hydroid colony - Göteborgs universitet
Hydroid colonies can vary greatly in composition. Many colonies can for example contain defensive polyps. The type of life cycle can vary between different colonies. There are hydroids that lack a colony building polyp stage, while with other specie the medusae stage is lacking.
The development and evolution of hydrozoan polyp and colony …
Hydrozoans represent an extremely diverse group of mostly colonial forms. Despite this tremendous diversity, many of the morphological differences between hydrozoan species can be attributed to simple changes in the relative position of regions/structures along the axes of the polyp and the stolon or hydrocaulus from which polyps bud.