158 Bellerochea horologicalis 鐘形中鼓藻 Phylum: Heterokontophyta 门：不等鞭毛門 Class: Mediophyceae 纲：中型硅藻綱 Order: Biddulphiales 目：盒形藻目 Family: Bellerocheaceae 科：中鼓藻科 Morphology Valves are usually elliptical and occasionally triangle. There are two forms of girdle view: broad girdle view and narrow girdle view. Narrow girdle views are frequently observed, and heights (pervalvar axis) are usually equal with or slightly longer than width (transapical axis). Broad girdle views are rarely observed, and the widths (apical axis) are usually equal with or slightly longer than heights (pervalvar axis). Valves are slightly convex on the center and concave at the ends, forming 4 short angles. Adjacent cells are united by short angles and valve center, forming a spiral curved chain structure of up to dozens of cells， with a radius of 400 to 600 μm. Two single spaces occur on the valve edge between the intercalary cells. One diatom species Licmophora abbreviata occasionally attach on the cell surface of Bellerochea horologicali. Chloroplasts are granular and numerous. 形態 殼面通常為橢圓形，偶爾呈三角形。 殼環面觀有寬殼環面觀和窄殼環面觀兩種形 態。 實際觀測中經常看到橢圓形的窄殼環面觀，細胞高度（貫殼軸）等於或略長 於寬（橫軸）。 寬殼環面觀較少觀測到，一般寬 （縱軸）大致等於或大於高 （貫 殼軸）。 殼面中央稍微隆起，邊緣下凹起形成四個短角，相鄰細胞通過短角以及殼 面中央相連形成螺旋彎曲的鏈狀結構。 鏈狀群體可多達幾十個，螺旋半徑400到 600微米。 相鄰細胞間殼面邊緣處有空隙。 鐘形中鼓藻細胞表面有時會附生另一 種硅藻短楔形藻Licmophora abbreviata 。 色素體小顆粒狀，數目多。 Ecology and distribution
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