=Plas´tids= [Gr. _plastos_, formed.] =Plat-y-hel-min´thes= [Gr. _platys_, flat; _helminos_, worm.] =Plat-y-rhi´næ= [Gr. _platys_, broad, flat; _rhis_, nose.] Monkeys of the New World having long tails and a wide septum to the nose. =Pleur-a-can´thus= [Gr. _pleuron_, rib; _akantha_, thorn.] =Pleu´ral= [Gr. _pleura_, rib, side.] =Pli-o-hip´pus= [Pliocene; Gr. _hippos_, horse.] =Pli´o-cene= [Gr. _pleion_, more; _kainos_, recent.] =Plumes= [Lat. _pluma_, small soft feather.] Feathers, especially when ornamental or large; or tufts of large and ornamental feathers. =Pneu-mo-coc´ci= [Gr. _pneumon_, lung; _kokkos_, berry.] Bacteria (spheroidal) found in those suffering from pneumonia. =Pol-y-dac´tyl-ism= [Gr. _polys_, many; _daktylos_, finger, toe.] The possession of an abnormally large number of fingers or toes. =Pol-y-mor´phism= [Gr. _polys_, many; _morphe_, form.] Exhibition by a group of animals, as a species, of different types of form or structure. =Po-lyp´te-rus= [Gr. _polypteros_, many-winged.] =Po-ly´o-don= [Gr. _polys_, many; _odous_, tooth.] =Pol´yp= [Gr. _polys_, many; _pous_, foot.] =Pol´y-the-ism= [Gr. _polys_, many; _theos_, god.] =Po-rif´e-ra= [Lat. _porus_, pore; _fero_, bear.] =Pre-Pa-læ-o-lith´ic= [Lat. _præ_, before; Palæolithic.] The period of time preceding the Ancient Stone Age. =Pri-ma´tes= [Lat. _primus_, first.] An order of mammals. =Pro-bos-cid´e-a= [Gr. _pro_, before; _bosko_, feed.] =Pro-nu´cle-us= [Lat. _pro_, before; _nucleus_, kernel.] =Pros-en-ceph´a-lon= [Gr. _pro_, before; _enkephalos_, brain.] A fundamental segment of the brain. =Pro-to-hip´pus= [Gr. _protos_, first; _hippos_, horse.] =Pro-toph´y-ta= [Gr. _protos_, first; _phyton_, plant.] =Pro´to-plasm= [Gr. _protos_, first; _plasma_, < _plasso_, form.] =Pro-top´te-rus= [Gr. _protos_, first; _pteron_, wing.] =Pro-to-zo´a= [Gr. _protos_, first; _zoon_, animal.] =Pseu-do-he-red´i-ty= [Gr. _pseudes_, false; Lat. _heredita_, heirship.] =Pseu-do-po´di-a= [Gr. _pseudes_, false; _pous_, foot.] =Psy-cho-zo´ic= [Gr. _psyche_, soul; _zoe_, life.] =Pter-i-doph´y-ta= [Gr. _pteris_, fern; _phyton_, plant.] =Pter-o-sau´ri-a= [Gr. _pteron_, wing; _sauros_, lizard.] =Pti-lo´pus cinc´tus.= =Pu´pa=, pl. =pupæ= [Lat. doll, girl, f. of _pupus_, boy.] The third stage of those insects that undergo a complete metamorphosis. Pupæ are often surrounded by protective envelopes called cocoons. =Quad-ru´la sym-met´ri-ca.= =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.] =Sai´tis pu´lex.=