Studies on the free-living protozoan fauna of estuaries in the coastal zone of Tamil Nadu, India Author Bindu, L. text Records of the Zoological Survey of India 2021 121 1 61 75 journal article 10.26515/rzsi/v121/i1/2021/141506 2581-8686 13186453 38. Difflugia oblonga Ehrenberg, 1838 Material examined : Mi-340, 2 ex. , Vellar estuary, 20.vii.2014 . Diagnosis : Test typically oblong with circular base; composed of big angular quartz crystals; pseudostome circular; dimension of test 90-115µm. Distribution in India : Assam , Himachal Pradesh , Meghalaya, Sikkim, Tamil Nadu, West Bengal .