Sponge spicule
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Spicules are structural elements found in most sponges. The meshing of many spicules serves as the sponge's skeleton and thus it provides structural support and potentially defense against predators.
Six-pointed triaxonal siliceous spicule from a glass sponge
Venus flower basket constructed from similar spicules
Demosponges can also have siliceous spicules. Some species obtain silica for building spicules by ingesting diatoms.
Sizes of different spicule types of marine sponges (A) Microsclere (sterraster) of Geodia spp.; (B) Microsclere (sigma) of Mycale quadripartita; (C) Megasclere (oxea) of Haliclona epiphytica; (D) Spicule tetralophose calthrop of homoscleromorph Plakina (A)
Hexactinellid
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Hexactinellid sponges are sponges with a skeleton made of four- and/or six-pointed siliceous spicules, often referred to as glass sponges. They are usually classified along with other sponges in the p
Sponge spicule
…structural elements that develop in a wide variety of sizes and three dimensional shapes. Among the four sub-clades of Porifera, three (Demospongiae, Hexactinellida, and Homoscleromorpha) produce skeletons of amorphous silica and one (Calcarea) of magnesium-calcite. It is these skeletons that are composed of the…
Haeckel Hexactinellae
Bolosoma stalked glass sponge
Venus' flower basket, Euplectella aspergillum
Euplectella aspergillum