The data about the shell ultrastructure of 6 interstitial testate amoebae: Chardezia caudata, Psammonobiotus balticus, P. golemanskyi, Corythionella minima, C. pontica and Micramphora pontica is presented for the first time. A biometric analysis of all of them, found in rich populations in the North-Eastern Black Sea littoral, is also accomplished. On the basis of the present investigations some morphometric descriptions and taxonomic diagnoses of the studied interstitial testate amoebae are supplemented and corrected. The summarized data on their geographical distribution so far in the World Ocean is given, too.