Proöt´ic, a. for n. An element of the auditory capsule.
Prosenceph´alon, n. A certain tract of the brain, the third from behind.
Pro´toplasm, n. Primitive common embryonic tissue, out of which different organs and parts are formed.
Protover´tebræ, n. pl. First trace of the backbones.
Protrac´tile, Protru´sile, a. Susceptible of being thrust forward or out, as the tongue of most woodpeckers.
Proventric´ulus, n. Part of gullet, usually enlarged, next to gizzard, having solvent glands for digestion. It is the true stomach of a bird, as distinguished from the gizzard or grinding stomach.
Prox´imal, a. Proximate; nearest or next to any centre or axis. Opposed to distal or terminal.
Psilopæ´des, n. pl. A group of psilopædic birds, further distinguished by being born weak and helpless, fed and reared in the nest. The term gymnopædes is synonymous.
Psilopæ´dic, a. Having down growing only from the future pterylæ, as the precursor of the future plumage, to which it is subsequently affixed for a while and then falls off.
Pso´as, n. Name of certain pelvic muscles.