Reference

Gregorio D. Fernandez-Leborans [Fernández-Leborans], A. Martin-Gonzales ((year 1981)): Morphological characteristics of four species of ciliates Gymnostomata (*Prorodon hispanicus* sp. nov., *Holophrya martitensis* sp. nov., *Holophrya castellanum* sp. nov. and *Perispira ovum*) – Annls Stn biol. Besse – 15: 221 - 230.