The hard covering of the colony, which retains its form after the animal is dead, is a kind of hardened skin: the apparent "cells" are the openings through which the individual zooids protrude themselves.
The zooids of the latter have each an independent head with a crown of tentacles, called the Lophophore (Crest-carrier); but the fixed ends of their bodies communicate with one another.
In a very large number of types the gonophores do not develop directly on the hydroid stem, but arise on specially modified zooidsresembling rudimentary trophosomes which have been named blastostyles by Allman.
The anterior asexual zooid continues to produce fresh sexualzooids by fission.
In the Hydromedusae an interesting series of relations between alternation of generations and the division of the zooids into gonophores and trophosomes can be made out.
In Myrianida also, where a chain of zooids is formed, the sexual elements seem to be confined to the individuals produced by budding.
The chief interest of its occurrence amongst the Hydromedusae and Siphonophora is the fact that its origin can be traced to a division of labour in the colonial systems of zooids so characteristic of these types.
Sexual reproduction does not take place at the same time as reproduction by fission, but both zooids produced are quite similar and multiply sexually.
They are modified medusa-zooids grown together and without tentacles.
Usually the central zooid in a Siphonophore to which the otherzooids are attached is not a bladder-like float, but is an upright tube of greater or less length.
Under the broad leaves of these protecting-zooids are a number of pear-shaped bodies which have a wide octagonal mouth-opening at their free end, and possess in their interior certain digestive glands.
These five zooids are formed by a process of embryonic fission.
This gives rise, while still an embryo, by a process equivalent to budding to four fully developed zooids (Ascidiozooids) similar to the parent form, and itself dies away.
Fresh systems become formed by a continuation of the process of budding, but the zooids of the secondary systems so formed are sexual.
The zooids long remain connected together, and united by a vascular tube with the Cyathozooid, and these connections are not severed till the latter completely atrophies.
The anterior part becomes segmented into four zooids or individuals, called by Huxley Ascidiozooids, which give rise to a fresh colony of Pyrosoma.
One of the special defensive zooids of certain hydroids.
One of the stellate or irregular clusters of intimately united zooids which are imbedded in, or scattered over, the surface of the common tissue of many compound ascidians.
An extension of the integument of the body, or of the body wall, from which buds are developed, giving rise to new zooids, and thus forming a compound animal in which the zooids usually remain united by the stolons.
Growing with one side adherent to a stem; - a term applied to the lateral zooids of corals and other compound animals.
Applied to sexual zooids of hydroids, that have a saclike form and do not become free; Ð opposed to phanerocodonic.
One of the secondary, and usually sexual, zooids produced by budding or fission from the primary zooids, in animals having alternate generations.
One of the free-swimming sexual zooids of Siphonophora.
Two forms of zooids in life project from small pores in the coral and resemble those of other hydroids.
Some of the zooids have very long tentacles; some have a mouth and digest food; others produce gonophores.
One of the cells or tubes which inclose the feeling zooids of Bryozoa.
The feeding and reproductive zooids hang down from the under side of the disk.
One of a peculiar kind of zooids situated on the polyp-stem of certain Siphonophora.
One of the zooids of certain Siphonophora, having somewhat the form, and the essential structure, of the bell of a jellyfish, and acting as a swimming organ.
The nutritive zooids of a hydroid, collectively, as distinguished from the gonosome, or reproductive zooids.
The zooids or polyps resemble small, elongated actinias united together at their bases by fleshy stolons, and thus forming extensive groups.
The zooids are situated along one edge of the side branches.
All the zooids of a colony are produced from one primary zooid, by successive buddings.
The production of numerous zooids by budding, especially when buds arise from other buds in succession.
All the zooids of a hydroid colony collectively, including the nutritive and reproductive zooids, and often other kinds.
One of the flat, leaflike, protective zooids, covering other zooids of certain Siphonophora.
The reproductive zooids of a hydroid colony, collectively.
The zooids or hydranths of marine hydroids are sometimes called hydras.
Such medusæ are the reproductive zooids or gonophores, either male or female, of the hydroid from which they arise, whether they become free or remain attached to the hydroid colony.
A cluster or aggregation of zooids of any compound animal, as in the corals, hydroids, certain tunicates, etc.
The latter contains the proximal moieties of the zooids and numerous but separate spicules.
After division the corallites continue to grow upwards, and their zooidsmay remain united by a bridge of soft tissue or coenosarc.
They resemble and are closely allied to certain families of the Cornulariidae, differing from them only in mode of budding and in the dispostion of the daughter zooids round a central, much-elongated mother zooid.
The pinnae are formed by the elongated autozooids, whose proximal portions are fused together to form a leaf-like expansion, from the upper edge of which the distal extremities of the zooids project.
It owes its commercial value to the beauty of its hard red calcareous axis which in life is covered by a cortex in which the proximal moieties of the zooids are imbedded.
In the first-named, the zooids are united only by their bases and the skeleton consists of loose spicules.
Thus the coenenchyma forms a stem, sometimes branched, from the surface of which the free portions of the zooids project.
Such modified zooids are called siphonozooids, their function being to drive currents of fluid through the canal-systems of the colonies to which they belong.
Defn: One of the stellate or irregular clusters of intimately united zooids which are imbedded in, or scattered over, the surface of the common tissue of many compound ascidians.
Producing sexual zooids by budding; -- said of the blastostyle of a hydroid.
Defn: The production of numerous zooids by budding, especially when buds arise from other buds in succession.
Defn: One of the flat, leaflike, protective zooids, covering other zooids of certain Siphonophora.
Defn: The reproductive zooids of a hydroid colony, collectively.
Defn: One of the individual zooids forming the compound organism of a polyzoan.
Note: Such medusæ are the reproductive zooids or gonophores, either male or female, of the hydroid from which they arise, whether they become free or remain attached to the hydroid colony.
Defn: One of the nutritive zooids of a hydroid colony.
The American species (Physalia arethusa) is brilliantly colored, the float being pink or purple, and bright blue; the zooids blue.
The zooids or hydranths of marine hydroids are sometimes called hydras.
Defn: The zooids of a compound anthozoan, collectively.
Defn: One of the special defensive zooids of certain hydroids.
The first three are almost entirely fabulous, and form the groundwork on which Boece and Buchanan afterwards based their historical fictions, which were exposed by Thomas Innes in his Critical Essay (i.
The forest policy of the United States may be said to have had its origin in 1799 in the enactment of a law which authorized the purchase of timber suitable for the use of the navy, or of land upon which such timber was growing.
A division of Hydroidea in which the zooids are naked, or not inclosed in a capsule.
The entire animal consists of a single cell which is variously modified; but in many species a number of these simple zooids are united together so as to form a compound body or organism, as in the Foraminifera and Vorticellæ.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "zooids" in a variety of sentences. We hope that you will now be able to make sentences using this word.
