Rasping plate, of Eunicidae, [270]

Rattulidae, [210], [225]

Rattulus, [212], [225], [226]

Ratzel, on Earthworms, [350]

Red Cat, [316]

Regeneration of lost parts, in Polyclads, [26];

in Triclads, [40];

in Cestodes, [77];

in Nemertinea, [115];

in Polychaeta, [278], [282];