六放海綿綱

六放海綿綱（Hexactinellida）為多孔動物門的一個綱。該綱動物具有矽質骨針，有些骨針能聚合成網狀的骨架。骨骼中無海綿質。本綱又稱為玻璃海綿。六放海綿綱動物大多數生活在 200～8500 米的海底。常被用做觀賞用途，主要生存於深海當中，這種海綿也與海裡的甲殼類生物共生，通常會有兩隻，一公一母的蝦類以此為家。在日本，骨骼經過人類製作之後，成為一種愛情的紀念品。英語俗名 Venus' Flower Basket。而受到一定程度的歡迎。

型態

形體大，骨骼全由矽質骨針組成，無海綿絲。典型的大骨針多為六射三軸針，互成直角，故又稱六射海綿綱。此外還有四射雙軸針等。骨針往往連線形成立體格架。小骨針呈六射星狀或雙盤狀。簡單複溝型，鞭毛室大；某些古生代種類還有單溝型。元古代晚期至現代。

在眾多能拿來跟玻璃相比的透明物種當中，最接近玻璃的應當屬維納斯花籃。它們長得像一個精緻的花瓶，因此而得名。它們也被稱作玻璃海綿，它們骨骼的主要成分是矽，這也是玻璃的主要成分。

主要特徵還有海綿特有的矽質骨針，並集結成纖巧的幾何網路，如偕老同穴（Venus's flower basket）一般，玻璃海綿中央腔內常寄居一對共生儷蝦，蝦在幼蟲的時候住進去，長大之後就逃不出去了。然後兩隻蝦被囚困其中，靠流進中央腔的水流而獲食物。這樣的海綿動物在日本成為了頗受歡迎的結婚禮物。

食性

玻璃海綿以從水中過濾而來的最小浮游生物為食，最大可以生長到兩米以上，它們花瓶般的身體構造為魚類、無脊椎動物以及其它海洋生物提供了完美的躲藏、產卵和生存的環境。玻璃海綿像珊瑚一樣開闢著自己的棲息地，在一定程度上，它們就像海床上的城市，無論它們生長在何處，總是會吸引來其它的海洋生物。

分類

六放海綿綱分為兩個亞綱：

雙盤海綿亞綱 Amphidiscophora
六放海綿亞綱 Hexasterophora

本綱包含以下目：

雙盤海綿目 Amphidiscosida
燈籠海綿目 Lychniscosida
松骨海綿目 Lyssacinosida
權杖海綿目 Sceptrulophora

目地位未定的科：

Aglithodictyidae
Asthenospongiidae
Celyphiidae
Cliefdenellidae
Colospongiidae
Cystispongiidae
Cystothalamiidae
Dictyospongiidae
Dierespongiidae
Docodermatidae
Hemidiscellidae
Hintzespongiidae
Hyalostellidae
Hydnodictyidae
Leptophragmatidae
Multivasculatidae
Pachyteichismatidae
Pattersoniidae
Pileolitidae
Pileospongiidae
Pillaraspongiidae
Plieolitidae
Porispongiidae
Protospongiidae
Sebargasiidae
Staurodermatidae
Stereodictyidae
Stromatidiidae
Teganiidae
Thaumastocoeliidae
Titusvillidae
Titusvilliidae
Triactinellidae
Uphantenidae
Wareembaiidae

目和科地位未定的屬：

Acanthactinella Hinde, 1887
Aglithodictya Hall & Clarke, 1898
Antrispongia Quenstedt, 1878
Arystidictyon
Asociatella Hurcewicz, 1985
Astroconia Sollas, 1881
Aulacosia Rauff, 1933
Aulodomus Schrammen, 1936
Australispongia Xiping & Knoll, 1996
Azyrtalia Nazarov, 1973
Baccispongia Quenstedt, 1877
Belonisia Rauff, 1933
Bothroconis King, 1850
Botryodictya Hall & Clarke, 1898
Caesaria Quenstedt, 1858
Calpidospongia Wu, 1989
Carbonella Hurcewicz & Czarniecki, 1986
Carinthiaspongus Krainer & Mostler, 1992
Caseispongia Quenstedt, 1878
Chelispongia Webby & Trotter, 1993
Chirospongia Miller, 1889
Cincliderma Hinde, 1883
Clepsydrospongia Hall & Clarke, 1898
Corticospongia Caster, 1939
Crepospongia Wu, 1989
Crucispongia Quenstedt, 1877
Cryptodictya Hall, 1890
Cyathophycella Rigby & Stuart, 1988
Cyrtobolia Pocta, 1883
Czarnockiella Hurcewicz & Czarniecki, 1986
Decumbispongia Botting, Muir, Li & Lin, 2013
Dialyscyphia Hurcewicz & Czarniecki, 1986
Diaretula Schmidt, 1879
Dilatispongia Botting, 2004
Diphyllospira Herrmann-Degen, 1980
Diplopleura Regnard, 1925
Dvorcia Nekvasilová & Štemproková, 1960
Emploca Sollas, 1883
Eubrochus Sollas, 1876
Euplectinella Termier, Termier & Thibieroz, 1990
Eutactostomium Herrmann-Degen, 1980
Farreopsis Schrammen, 1924
Flosculus Xiping & Knoll, 1996
Gonamispongia Korshunov, 1968
Gongylospongia Hall & Clarke, 1898
Griphodictya Hall & Clarke, 1898
Haljalaspongia Botting & Rhebergen, 2011
Hallodictya Hall & Clarke, 1898
Helicodictya Hall & Clarke, 1898
Hemidiagoniella Botting, 2004
Hemidiscella
Hexactractiella
Hexatractiella Mehl, 1996
Hillendia Reid, 1964
Hintzesnonaia
Hodsia Moisseev, 1939
Holasterella
Holasterella Carter, 1879
Hunteria Van Soest & Hooper, 2020
Hyalocaulus Marshall & Meyer, 1877
Hydnocerina Clarke, 1920
Idiodictyon de Laubenfels, 1955
Iowaspongia Thomas, 1923
Irpaspongia Mehl & Mostler, 1994
Ithacadictya Caster, 1939
Kaiyangites Qian & Yin, 1984
Koleostoma Regnard, 1925
Kometia Webby & Trotter, 1993
Konyrium Nazarov & Popov, 1976
Krainerella Krainer & Mostler, 1992
Laocaetis
Larispongia Carrera, 1998
Lecanocoelospongia Wu, 1989
Lithospongia Duchassaing & Michelotti, 1864
Lobospongia Hurcewicz, 1985
Lonsda de Laubenfels, 1955
Lopanella Pocta, 1883
Lysactinella
Mastodictya Hall & Clarke, 1898
Mastodictyum Sollas, 1883
Megastylia
Mimeticosia
Multiloqua de Laubenfels, 1955
Multivasculatus Howell & Van Houten, 1940
Mysterium de Laubenfels, 1955
Nephelispongia
Nitidus de Laubenfels, 1955
Octobrum de Laubenfels, 1955
Oospongia Wu, 1989
Oxyrhizium Schrammen, 1912
Ozospongia
Pachaulidium Schmidt, 1880
Pachylepisma Schrammen, 1902
Palaeophragmodictya Gehling & Rigby, 1996
Palaeorossella Li et al., 2019
Palaeostauronema
Paleophragmodictya Gehling & Rigby, 1996
Paleostauronema Hurcewicz, 1985
Paracraticularia Schrammen, 1936
Parahexactinella Reid, 1963
Petalope Pocta, 1883
Phormosella Hinde, 1888
Pinnatispongia Xiping & Knoll, 1996
Placochlaenia Pomel, 1872
Placospongia Wu, 1989
Plecteurete Herrmann-Degen, 1980
Plecteurette
Plectoderma Hinde, 1883
Plectospyris Sollas, 1883
Pleodioria Öpik, 1961
Polonoscyphia Hurcewicz, 1985
Polyosepia
Polyplectella Ruedemann, 1925
Polyptycha Defretin-Lefranc, 1961
Polyschema Oppliger, 1915
Polystigmatium Schrammen, 1912
Polysyge
Poriferella Hurcewicz, 1985
Porospongia d'Orbigny, 1849
Prenehydnoceras Hurcewicz & Czarniecki, 1986
Proeurete Schrammen, 1902
Protoarmstrongia Caster, 1941
Protremadictyon Hurcewicz, 1985
Psephosyllogus Schrammen, 1936
Pseudotragos Nutsubidze, 1965
Pyrenospongia Wu, 1989
Ramulospongia Hurcewicz, 1985
Repospongia Hurcewicz & Czarniecki, 1986
Retifungus Rietschel, 1970
Rhabdosispongia Hall & Clarke, 1898
Rhabdostauridium Schmidt, 1880
Rhakistella Weller, 1931
Rhogostomium Schrammen, 1936
Rhombedonium Schrammen, 1936
Rhombodictyon Whitfield, 1886
Rhopalicna
Rigbykia Özdikmen, 2009
Roemerispongia Hall & Clarke, 1898
Rosella Vassiljeva, 1988
Rugosoderma Howell, 1957
Scotospongia Krainer & Mostler, 1992
Sestrocladiella Howell, 1957
Silicunculus Bengtson, 1986
Solusrectus Botting, 2004
Spiractinella Hinde, 1887
Sulugurella Pelman, Ermak, Fedorov, Luchinina, Zhuravleva, Repina, Bondarev & Borodaevskaya, 1990
Sycodictya Ruedemann, 1925
Synaulia Pocta, 1883
Teganiella Rigby, 1985
Teganium Rauff, 1894
Testiispongia Rigby, 1983
Textispongia Quenstedt, 1877
Thamnodictya Hall, 1884
Uphantena
Uralonema
Ursaspongia Rigby, 1985
Ventriculita
Walcottella de Laubenfels, 1955
Xenoschrammenus
Xylospongia Hérenger, 1942
Zittelospongia Malfatti, 1901