A new species of Salmacina Claparède, 1870, herein described, was found in dense aggregations on the coral Mussismilia hispida (Verrill, 1868). Salmacina ceciliae n. sp. is characterised by rounded enlarged cells located subdistally on the radioles, distally on the pinnulae, and, in most of the specimens, many eyespots are present in the distal third of radioles and pinnulae. Comparisons between S. ceciliae and the other species of the genus are provided.