PLA- 



244 



PLE- 



plastogamy (plastog'ami) n. [Gk. 

 plastos, formed ; games, marriage.] 

 Union of distinct protozoan indi- 

 viduals with fusion of cytoplasm 

 but not of nuclei (zool.}. 



plastral (plas'tral) a. [F. plastron, a 

 breast-plate.] Pert, a plastron. 



plastron (plas'tron) n. [F. plastron, 

 a breast-plate.] The ventral bony 

 shield of Tortoises and Turtles ; 

 some other corresponding struc- 

 tures (zool.}. 



plate (plat) n. [L. platus, flat.] A 

 flat, broad, plate-like structure or 

 surface ; a lamina, scale, disc, etc. 



platydactyl (plat'idak'til) a. [Gk. 

 platys, flat ; daktylos, a finger.] 

 With flattened-out fingers and toes, 

 as certain tailless Amphibians 

 (zool.}. 



platysma (platiz'ma) n. [Gk. platysma, 

 a flat piece.] A broad sheet of 

 muscle beneath the superficial fascia 

 of the neck (anat.}. 



plectonephridia (plek'tonefrid'ia) n. 

 plu. [Gk.plektos, twisted ; nephros, 

 kidney.] Nephridia of diffuse type 

 formed of networks of fine excretory 

 tubules lying on the body-wall and 

 septa of certain Oligochaetes ; 

 plectonephria, nephridia (zool.}. 



pleiocyclic (pll'osfk'llk) a. [Gk. pleion, 

 more ; kyklos, circle.] Living 

 through more than one cycle of 

 activity, as a perennial plant (bot.}. 



pleiomerous (pliom'erus) a. [Gk. 

 pleion, more ; meros, part.] Having 

 more than the normal number of 

 parts, as of petals or sepals (bot.}. 



pleiophyllous (plfoftTus) a. [Gk. 

 pleion, more ; phyllon, leaf.] Having 

 more than the normal number of 

 leaves or leaflets (bot.}. 



pleiotaxy (pli'otak'si) n. [Gk. pleion, 

 more ; taxis, arrangement.] A 

 multiplication of whorls, as in 

 double flowers (bot.}. 



pleomorphous (ple'6m6r'fus) a. [Gk. 

 pleon, more ; morphe, form.] Poly- 

 morphous ; having two or more 

 distinct forms occurring in one life- 

 cycle (biol.}. 



pleon (ple'on) n. [Gk. pleein, to sail.] 

 The abdominal region of Crus- 

 taceans (zool.}. 



pleopod (ple'opod) n. [Gk. pleein, to 

 sail ; pous, foot.] An abdominal 



appendage or swimming -leg of 

 Crustaceans (zool.}. 



plerocestoid (pler'oses'toid) n. [Gk. 

 pleros, full ; kestos, girdle ; eidos, 

 form.] A inetacestode, or sexless 

 encysted stage of a cestoid worm 

 (zool.}. 



plerome (pleYom) n. [Gk. pleroma, 

 completion.] The core or central 

 part of an apical meristem (bot.}. 



pleura (ploo/a) n. [Gk. pleura,_ a 

 side.] A serous membrane lining 

 the thoracic cavity and investing 

 the lung (anat.}. 



pleural (ploor'al) a. [Gk. pleura, a 

 side.] Pert, a pleura or pleuron ; 

 as pleural ganglia (zool.}. 



pleuralia (ploora'lia) n. plu. [Gk. 

 pleura, a side.] Defensive spicules 

 scattered over the general surface 

 of the body (zool.}. 



pleurapophysis (ploor'apofisls) n, 

 [Gk. pleura, a side ; apo, from ; 

 physis, growth.] A lateral verte- 

 bral process or true rib (zool.}. 



pleurite (ploor'lt) n. [Gk. pleura, a 

 side.] A pleuron. 



pleurobranchiae (ploor'obrang'kie) n. 

 plu. [Gk. pleura, a side ; brangchia, 

 gills.] Pleurobranchs, or gills 

 springing from the lateral walls of 

 the thorax of certain Arthropods 

 (zool.}. 



pleurocarpous(ploor'6kar'pus) a. [Gk. 

 pleura, a side ; karpos, fruit.] Appl. 

 Mosses with fructification on lateral 

 branches (bot.}. 



pleurocentrum (ploor'osen'triim) n. 

 [Gk. pleura, a side ; L. centrum, a 

 centre.] A lateral element of the 

 centrum of many Fishes and fossil 

 Amphibians (zool.}. 



pleurocerebral (ploor'6'seYebral) a. 

 [Gk. pleura, a side ; L. cerebrum, 

 brain.] Pert, pleural and cerebral 

 ganglia, in Molluscs (zool.}. 



pleurodont (ploor'odont) a. [Gk. 

 pleura, side ; odous, tooth.] Having 

 teeth fixed by their sides to the 

 lateral surface of the jaw ridge, as 

 in some Lizards (zool.}. 



pleuron (ploor'on) n., pleura (ploor'a), 

 plu. [Gk. pleuron, a side.] The 

 external lateral pieces of the body 

 segments of Arthropods ; the 

 lateral extensions of Crustacean 

 shells (zool.}. 



