外殼膜

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提示:本条目的主题不是外套膜
The shell of Stenotrema florida, a land snail or terrestrial gastropod. The periostracum of this species has minute hairs, giving the snail a velvety feel
A yellowish tan periostracum is visible on the lower two thirds of this juvenile (8 cm) valve of the marine bivalve Spisula solidissima
The dark periostracum is flaking off of this dried-out valve of the "ocean quahog", marine bivalve Arctica islandica, from Wales
Fresher valves of Arctica islandica with periostracum intact. Note that the periostracum is partially worn off on the umbo, this is because the umbo is older than the rest of the shell and also projects more: it has been exposed to more abrasion during the life of the clam

外殼膜periostracum),亦作殻皮[1]:251,是軟體動物腕足动物门物種的外殼之外的一層包裹物;但兩個分類的外殼膜由不同材質組成,亦使這兩種外殼膜表現出不同的特徵。在軟體動物,主要為腹足綱及雙殼綱最常見,但在頭足綱如Allonautilus scrobiculatus之類的物種也有外殼膜。外殼膜與其包裹的外殼及外殼上的其他分層都是整個外殼的整全部分,也成為了這些物種的可分辨外觀。

Periostracum這個字由perio-(包圍)和stracum兩部分組成,意思就是「包圍着外殼」,包圍着外殼的鈣質層(ostracum)[2]

軟體動物[编辑]

成份[编辑]

軟體動物的外殻膜是一層覆蓋在新鮮殻表面的纖維狀角質物[1]:251,這種角質蛋白叫作貝殻蛋白英语conchiolin,主要由鞣製的蛋白質組成,與其他生物上皮組織組成的角質層相似[3]

功能[编辑]

Description[编辑]

Hairs on gastropod shells[编辑]

腕足动物[编辑]

腕足动物门的外殼膜在不同物種由不同成份組成,包括有:糖胺聚糖甲殼素幾丁質蛋白质,當中以幾丁質為主。 在這些腕足动物的外套膜邊沿上相對比較新的細胞所分泌的物質將外殻膜延展,但又會被其外套膜上層較新的細胞所取代,然後轉變功能成為為其外殻分泌礦物質構築物的細胞[7]

參看[编辑]

參考文獻[编辑]

  1. ^ 1.0 1.1 Dance, S. Peter. 世界貝殼圖鑑 2nd. 2008. 
  2. ^ Periostracum. Dictionary.com Unabriged. Random House. [2015-05-10]. 
  3. ^ Brusca, R.C. and Brusca, G.J. 1990. Invertebrates. Sinauer Assoc., Inc, Sunderland, Massachusetts. p. 716.
  4. ^ 4.0 4.1 4.2 Marin, Frédéric; Luquet, Gilles. Molluscan shell proteins. Comptes Rendus Palevol. 2004, 3 (6–7): 469. doi:10.1016/j.crpv.2004.07.009. 
  5. ^ Caron, Jean-Bernard; Scheltema, Amélie; Schander, Christoffer; Rudkin, David. Reply to Butterfield on stem-group "worms": Fossil lophotrochozoans in the Burgess Shale. BioEssays. 2007, 29 (2): 200–2. PMID 17226817. doi:10.1002/bies.20527. 
  6. ^ 6.0 6.1 6.2 6.3 Pfenninger, M.; Hrabáková, M.; Steinke, D.; Dèpraz, A. Why do snails have hairs? A Bayesian inference of character evolution [為什麼蝸牛會有毛髮?]. BMC Evolutionary Biology. 2005, 5: 59. PMC 1310604. PMID 16271138. doi:10.1186/1471-2148-5-59 (英语). 
  7. ^ Doherty, P.J. The Lophophorates. (编) Anderson, D.T. Invertebrate Zoology 2. Oxford University Press. 2001: 356–363. ISBN 0-19-551368-1. 

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