374 GLOSSARY. 



Pneumatophore (Gr. jmemna, air ; phero, I carry). The air-bladder of the 



Fhysophoridoj. 

 PoDOSOMATA (Gr. poiis, foot ; soma, body). An order of Arachnida. 

 PoiSERS. See Balancers. 



PoLLEX (Lat. the thumb). The innermost of the normal five digits of the fore- 

 foot of the higher Vertebrata. The thumb of man. 

 PoLYCH^TA (Gr. polus, many ; chaite, bristle). The order of the highpr Anne- 



lides, comprising the Sea-worms, in which the foot-tubercies carry tufts of 



bristles. 

 PoLYCYSTiNA (Gr. polus, many ; kustis, a bladder). An order of Protozoa. 

 Polygamous (Gr. polus, many ; games, marriage). Applied to cases iu which 



one male consorts with several females. 

 POLYGASTRICA (Gr. polus, njany ; paster, stomach). The name applied by 



Ehrenberg to the Infusoria, under the belief that they possessed many 



stomachs. 

 PoLYPARV. The hard chitinous covering secreted by many of the Hydrozoa. 

 Polype (Gr. pol%is, many ; pous, foot). Restricted in modem nsage to the 



single individual of a simple Actinozoon, or to the separate zooids of a 



compound Actinozoun. 

 PoLYPiDE. The separate zooid of a Polyzoon. 

 POLYPiDOM. Synonymous with polypary, but often aiiplitd to the Polyzoa, 



as well as to the Hydrozoa. 

 PoLYPiTE. The separate zooid of a Hydrozodn. 

 PoLYTHAL\MOUS {Gt. pohis, many; thalamos, chamber). Many-chambered. 



Applied to the shells of FiiramiiLifera and Cephalopoda. 

 PoLYZOA (Gr. polus, many; zoon, animal). The Sea-mosses, and Sea-mats, 



forming the lowest class of the MoUusca. 

 PomPERA (Lat. poms, a pore ; fero, I carry). The Sponges, so called because 



the body is furnished with canals terminating on the surface in larger or 



smaller openings. 

 pR.<EMOLARS (Lat. pnr, before ; molares, grinders). The teeth which succeed 



tiie molars of the milk-set of teeth. 

 Pb^-(ESOphageal. Situated in iront of the gullet. 

 Proboscidea (Gr. proboscis, the snout). The order of Mammals comprising 



the Elephants. 

 Proccelous (Gr. pro, front ; l-oilos, hollow). Applied to vertebras, the bodies 



of which are hollow or concave in front. 

 Protophyta (Gr. protos, first ; phyton, plant). The lowest division of 



plants. 

 Protoplasm (Gr. protos, first; 'plosf^o, I mould). The elementary basis of 



organised tissues. Seen in its least modified form in the " sarcode " of the 



Protozoa. 

 Protozoa (Gr. protos, first; zoon, animal). Tlie lowest division of the Animal 



Kingdom, 

 Proximal (Lat. proxivius, next). The slowly growing, comparatively fixed 



extremity of a limb or of an organism. 

 PsALTERiUM (Lat. a stringed instrument). The third stomach of the 



Ruminants. 

 PsEUDOH^EMAL (Gr. pscudos, false ; haima, blood). The vascular system of 



the Annelida. 

 Pseudo-hearts. Contractile cavities connected with the reproduclive system 



of the Brachiopoda. 

 Pseudopodia (Gr. pseudos, falsity ; podes, feet). The temporary extensions of 



the body-substance which are put forth by the Jihizopoda at will, and which 



serve both for locomotion and for prehension. 

 Pteropoda 'Gt. ptermi, awing; podes, feet). A class of MoUusca swimming 



by means of fins attached to the sides of the head. 

 Pterosauria (Gr. p'teron, a wing; saura, a lizard). An extinct order of 



Reptiles. 

 Pulmonary (Lat, pulmo, a lung). Connected with the lungs, 

 PuLMONATE. Possessing lungs. 



