RHINOTHE´CA, _n._ Covering of the upper mandible. (13.)

RHIZONYCH´IUM, _n._ Terminal bone of a toe bearing a claw. (122.)

(Little used.)

RHOM´BOID, _a._ Lozenge-shaped. Name of a muscle of the shoulder-blade.

RIC´TUS, _n._ Gape of the mouth.