Lipid composition and fatty acid composition were characterized in the membrane of a marine ciliate protozoan (Uronema marinum). Phospholipids accounted for 70% of total lipid, and the remainder was neutral lipids. Total phospholipids were separated as phosphatidylcholine $(24.26\%)$, phosphatidylethanolamine $(22.21\%)$, phosphatidylinositol $(6.14\%)$, phosphatidylserne $(5.11\%)$, cardiolipin $(3.07\%)$ and unidentified phospholipids $(28.72\%)$ through high performance liquid chromatography (HPLC). Fatty acid composition of neutral lipids and phospholipids was determined by gas chromatography (GC), based solely on comparision of retention times. In neutral lipids, the most abundant fatty acid group was monounsaturated fatty acid $(48.3\% of total fatty acids)$ with oleic acid (18:1) and nervonic acid (24:1). Saturated fatty acids comprised $29.6\%$ of total fatty acids, with palmitic acid (16:0), stearic acid (18:0) ane myristic acid (14:0), and polyunsaturated fatty acid accounted for $33.0\%$ with $Di-homo-gamma-linolenic$ acid (20:3) and linoleic acid (18:2). Wherease phospholipids predominantly contained the fatty acid group in the following order: polyunsaturated fatty acids $(52.7\%;of;total;fatty;acids)$ with linoleic acid (18:2) and $gamma-linolenic$ acid (18:3) > monounsaturated fatty acids $(28.5\%;of;total;fatty;acids)$ with oleic acid (18:1) and palmitoleic acid (16:1) > saturated fatty acids $(25.5\%;of;total;fatty;acids)$ with palmitic acid (16:0), stearic acid (18:0) and myristic acid (14:0).
