PNE- 



246 



POL- 



cavities, as in the bones of flying 

 birds (zool.). 



pneumatized (nu'matlzd) a. [Gk. 

 pneuma, air.] Furnished with air 

 cavities. 



pneumatocyst (nu'matosTst) n. [Gk. 

 pneuma, air ; kystis, a bladder.] 

 The air-bladder or swim-bladder of 

 Fishes (zool^j. 



pneuinatophore (nu'matofor) n. [Gk. 

 pneuma, air ; pherein, to bear.] The 

 air-sac or float of Siphonophores 

 (zool.} ; an air-bladder of marsh or 

 shore-plants (hot.). 



pneumatopyle (nu'matopll) n. [Gk. 

 pneuma, air ; pyle, gate.] One of 

 the pores of a pneumatophore, 

 opening above to the exterior in 

 certain Siphonophores (zool.}. 



pneumogastric (nu'mogas'trik) a. 

 [Gk. pneuma, air ; gaster, stomach.] 

 Appl. the tenth cranial nerve, 

 supplying heart, lungs, and viscera 

 (<z#a/.). 



pneumotaxis (nu'motak'sis) n. [Gk. 

 pneuma, air ; taxis, arrangement.] 

 Reaction to the stimulation of 

 carbon dioxide in solution ; cf. 

 aerotaxy (phys.\ 



pod (pod) n. [M.E. pod, a bag.] A 

 superior, one-celled, one- or many- 

 seeded fruit of two valves ; a husk 

 (bot.\ 



podal (pS'dal) a. [Gk. pous, a foot.] 

 Pert, feet ; j>edal. 



podeon (po'deSn) n. [Gk. pous, foot.] 

 The petiole or slender middle part 

 of the abdomen of Hymenoptera 

 uniting propodeon and metapodeon 



podetiiform (pode'shnform) a. [Gk. 



pous, foot ; L. forma, shape.] Re- 



sembling a podetium (hot.). 

 podetium (pode'shium) n. [Gk. pous, 



foot.] A stalk-like elevation from 



the thallus of some Lichens (bot.\ 

 podeum, a podeon. 

 podex (po'dgks) n. [L. podex, rump.] 



The region about the anus. 

 podlcal (pSd'ikal) a. [L. podex, rump.] 



In the anal region ; appl. a pair of 



small hard plates beside the anus 



of Arthropods (zool.~). 

 podite (pod'It) n. [Gk. pous, foot.] 



A Crustacean walking leg. 

 podium (po'dium) n. [Gk.pous, foot.] 



A foot or footlike structure (biol.\ 



podobranchiae (p5dobrang'kle) n. plu. 

 [Gk. pous, foot ; brangchia, gills.] 

 Podobranchs or foot-gills, springing 

 from the coxopodites of the thoracic 

 appendages of certain Arthropods 

 (zool.}. 



podocephalous (podokefalus, -s6f-) 

 a. [Gk. pous, foot ; kephale, head.] 

 Having a head of flowers on a long 

 stalk (&?/.) 



podoconus (pod'b'ko'nus) n. \G\a.pous, 

 foot ; konos, cone.] A conical mass 

 of endoplasm connecting the central 

 capsule with the disc of Sarcodina 

 (zool.}. 



podocyst (pod'osist) n. [Gk. pous, 

 foot ; kystis, bladder.] A pedal 

 sinus or caudal vesicle in certain 

 Gasteropods (zool.}. 



pododerm (pod'oderm) n. [Gk. pous, 

 foot ; derma, skin.] The dermal 

 layer of a hoof, within the horny 

 layer (zool^). 



podogynium (pod'qjm'ium) n. [Gk. 

 pous, foot ; gyne, a female.] A stipe 

 supporting the gynoecium (dot.*). 



podomere (pod'omer) n. [Gk. pous, 

 foot ; meros, part.] A limb segment 

 of Arthropods (zool.}. 



podophthalmite (pod'ofthal'mlt) n. 

 [Gk. pous, foot ; ophthalmos, eye.] 

 In Crustaceans, the eyestalk seg- 

 ment farthest from the head (zool.~). 



podotheca (pSd'othe'ka) n. [Gk. 

 pous, foot ; theke, a -box.] A foot 

 covering, as of Birds or Reptiles. 



pogonion (pogo'nion) n. \G\a.pogonion, 

 little beard.] The most prominent 

 point of the chin as represented on 

 the mandible (anat.}. 



poikilothennal (poik'ilothgr'mal) a. 

 [Gk. poikilos, various ; thermos, 

 heat.] Appl. cold-blooded animals, 

 or those whose temperature varies 

 with that of thesurroundingmedium; 

 cf. homolothermal (phys.\ 



poikilothermous, poikilothermal. 



poisers, halteres, which see. 



polar (po'lar) a. [Gk. polos, a pivot.] 

 In the region of the end of an 

 axis ; at a pole. 



polar body, one of two cells divided 

 off from the ovum during matura- 

 tion, before the germ-nuclei fuse 



polar nuclei, a nucleus remaining 

 at each end of an angiosperm em- 



