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 16. Centropyx isecornis ( Ehrenberg, 1841) Material examined : Mi-326, 3 ex. , Coleron estuary, 08.xii.2013 . Diagnosis : Test discoid, dark brown in colour; outline slightly irregular, spines absent and covered with quartz particles; flanks slightly arched and more elevated towards the posterior part; aperture eccentric and circular; test diameter 130-200µm. Distribution in India : Assam , Andhra Pradesh , Arunachal Pradesh , Himachal Pradesh , Kerala (Nilgiri Biosphere Reserve), Manipur , Meghalaya , Nagaland , Sikkim , Tamil Nadu (present record), West Bengal .