The morphological characteristics of two species of protozoan marine scuticociliates, belonging to the genera Pleuronema and Schizocalyptra, have been studied and, with regard to the species of the genus Pleuronema, the aspects relative in particular to the somatic and buccal infraciliature are described, taking into account the biometric data of 26 different features. This species is compared with the 15 most similar species and different strains of species, and it is concluded that it is a new species, P. lynni. The species belonging to the genus Schizocalyptra (S. marina n. sp.) has a fibrillar system that corresponds to the buccal area that has not been observed before, as well as other structural components, which have been discussed in relation to Schizocalyptra magna (Dragesco, 1968), the only known species.