Qua-ter´na-ry [Lat. quaternarius, consisting of four.]
Ra-ti´tæ [Lat. ratis, raft.] A group of birds whose sternum is without a keel; aborted wings. Including ostriches, emus, moas, rheas, etc.
Rhi-noc´e-ros [Gr. rhis, nose; keras, horn.]
Rhi-zop´o-da [Gr. rhiza, root; pous, foot.]
Ro-den´ti-a [Lat. rodo, gnaw.]
Ro-ta´li-a Frey´er-i [Lat. rota, wheel; Freyer.]
Ro-ta-to´ri-a [Lat. rota, wheel.]
Ro´ti-fer [Lat. rota, wheel; fero, bear.]
Ru´mi-nant [Lat. ruminans, ruminate.]