Eutintinnus (you-tin-tin-us), one of the tintinnid ciliates. These are mostly marine choreotrichs in which the cell is located within an open lorica which it drags around while it swims. The different genera and species are mostly distinguished by the different appearances of the lorica. This genus has a conical lorica which is open at both ends. With an adoral zone of membranelles located around the top end of the cell. Differential interference contrast.