A detailed study on Recent Ostracoda was carried out in twenty-six surface sediment samples collected from shelf region of the Southwestern part of Bay of Bengal. A total of 21 species of Ostracoda belonging to 18 genera have been identified, of which, seven species are abundant (>5%). The Q-mode and R-mode cluster analyses of the abundant species resulted in two assemblage defining different microenvironments. The shallowest assemblage (I) from 10 to 80 m water depth is characterised by Hemikrithe Orientalis, Pterygocythereis chennaiensis and Lankacythere multifora which are associated with sand to slightly muddy sand. The second assemblage (II) from 80 to 200 m water depth is associated by Keijella reticulata, Bairdoppilata paraalcyonicola, Actinocythereis scutigera and Stigmatocythere indica and the nature of sediments varies from slightly muddy sand to slightly sandy mud. The sediments from 50-100 m water depth are foundto contain higher concentration of organic matter (TOC and TN) suggesting the high productivity zone. The C/N ratio value ranges from 4 to 8 in 52% of sediment samples indicating both marine and terrestrial source. The shallower part of the seafloor up to 30 m depth is dominated by sandysediments, reflecting the occurence of high-energy conditions. The higher mud content in the deeper part is due to the prevalance of low energy condition. The carapace-valve ratio (1:9) indicates that the study area experiencing a slower rate of sedimentation. Our study results revealed that the distribution of Ostracoda in the Southwestern part of Bay of Bengal is controlled by the type of sediment, depth and physicochemical parameters of the bottom water.

在从孟加拉湾西南部陆架区域收集的二十六个地表沉积物样本中，对最近的龙骨科进行了详细研究。总共鉴定出了21个属于18属的蠕形目，其中7种是丰富的（> 5％）。对丰富物种的Q型和R型聚类分析导致两个组合，定义了不同的微环境。从10到80 m水深最浅的组合（I）的特征是Hemikrithe Orientalis，Pterygocythereis chennaiensis和Lancancythere多孔，它们与沙子或微泥沙有关。从水深80至200 m的第二个组合（II）与网纹藻（Keijella reticulata），贝氏拟白伞（Bairdoppilata paraalcyonicola），猕猴桃和印度的柱头沉积物的性质从微泥沙到微沙泥不等。发现水深为50-100 m的沉积物中含有较高浓度的有机物（TOC和TN），表明该地区属于高产区。在52％的沉积物样本中，C / N比值的范围为4到8，指示海洋和陆地来源。高达30 m深度的海底较浅部分主要为沙质沉积物，反映出高能条件的发生。在较深部分较高的泥浆含量是由于普遍存在低能状态。甲壳与阀门的比率（1：9）表明研究区域的沉积速度较慢。我们的研究结果表明，孟加拉湾西南部的骨纲动物的分布受沉积物类型的控制，