cryptomonadina

from The Century Dictionary.

• In Ehrenberg's system of classification (1836), a family of loricate infusorians of persistent form, undergoing complete fission and lacking an intestine and appendages.
• In Stein's system (1878), a family of flagellate infusorians, represented by the genera Cryptomonas, Chilomonas, and Nephroselmis.
• noun A family of Protozoa, of the order Flagellata, having either a colored or a colorless body, usually compressed laterally, without true cuticle, with two long anterior flagella, and the anterior end obliquely truncated. It includes Chilomonas, Cyathomonas, Cryptomonas, and Oxyrrhis.