344 Gl.OSSARY. 



vascular connection is established in the higher MaTmnalia between the 



mother and the foetus. 

 Pla-oen'tal. Possessing a placenta, or connected with the placenta. 

 Plao'oid (Gr. plax, a plate ; eidos, form). Applied to the irregular hony 



plates, grains, or spines, which are found in the skin of various fishes 



(Elasmohraachii). 

 Pla-si-os'to-mi (Gr. plagios, transverse ; stoma, mouth). The Sharks and 



Eays, in which the mouth is transverse, and is placed on the under surface 



of the head. 

 Pla-n ab'i-da (Gr. plane, wandering). A sub-order of the Turbellaria. 

 Plak-ti-oea'da. 

 Plant'i-gkade (Lat. planta, the sole of the foot ; gradior, I walk). Applying 



the sole of the foot to the ground in walking. 

 Plan'u-la (Lat, planus, flat). The oval ciliated embryo of certain of the My- 



drozoa. 

 Plas'teon. The lower or ventral portion of the bony case of the Chelonians. 

 Plat-t-el'mi-a (Gr. platus, broad ; and Ttelmme, an intestinal worm). The 



division of Scoledda comprising the Tape-worms, etc. 

 Plat-y-khi'na (Gr.^totis, broad ; rhines, nostrils). A group of the Quadru- 



majia. 

 Ple-8i-o-sau'stj3 (Gr. plesios, near to ; and sawrus, lizard). 

 Plec'ea (Gr. for the side). The serous membrane covering the lung in the 



air-breathing Vertebrates. 

 Pleu'eon (Gr. pleuron, a rib). The lateral extensions of the shell of Crustacea. 

 Plu'te-us (Lat. for a pent-house). The larval form of the JSelwnoidea. 

 Pheu-mat'io (Gr. pneuma, air). Filled with air. 

 Pkeu-jiat'o-oyst (Gr. pneuma, air ; and hustisj cyst). The air-sac or float of 



certain of the Oceanic Eydrozoa {Physophondm). 

 Pheu-mat'o-phoee (Gr. pneuma, air ; and^pAsro, Icarry). The proximal dilata- 

 tion of the coenosaro in the Physaphoridos which surrounds the pneumatocy st. 

 Pneu-iio-skel'e-ton (Gr. pneuma; and sheletos, dry). The hard structures 



which are connected with the breathing organs (e. g., the shell of Molluscs). 

 Pon-oPH-THAL'MATA (Gr. pous, foot ; and opMAalmoe,ey&). The division of 



Crustacea in which the eyes are borne at the end of long foot-stalks. 

 Pod-o-som'a-ta (Gr. pous, toot : soma, body). An order of Araehnida. 

 Po-eph'a-sa (Gr.^o«, grass; phago, I eat). A group of the Marsupials. 

 Pois'ees. 

 Pol'lex (Lat. for the thumb). The innermost of the five normal di^ts of the 



anterior limb of the higher Vertebrates. In man, the thumb. 

 Pol-y-oys-ti'na (Gr. polus, many ; and Jcustis, a cyst). An order of R-otcaoa, 



with foraminated siliceous shells. 

 Po-LTo'A-Moua (Gr. polus: and games, marriage). 

 Pol-y-gas'tei-ca (Gr. polus ; and gaster, stomach). The name applied by 



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



stomachs. 

 Pol'y-pa-ry (Sit. polus; and pario, I produce). The hard chitinous cover- 

 ing secreted by many of the Hydrozoa. 

 Polype (Gx. polus, many; pons, foot). Ecatrioted to the single individual 



of a simple Actinoioon, such as a Sea-anemone, or to the separate zooids of 



a compound Actinozoim. Often applied indiscriminately to any of the 



Calenterata, or even to the Polyzoa. 

 Pol'y-pide. The separate zooid of a Polyzoon. 



PoL-Yp'i-DOM. The dermal system of a colony of a Eydrozoin, or B>lyzoon. 

 Pol'y-pite. The separate zooid of a Hydrozoon. 

 Pol'y-stome (Gr. polus, many ; and stoma, mouth). Having many mouths ; 



applied to the Acinetce among the Protozoa, 

 Pol-y-thax'a-mous (Gr. polus; and thdlamos, chamber). Having many 



chambers : applied to the shells o( Foraminifera and Cephalopoda. 

 Pol-y-zo'a (Gr. polus ; and zoiin, animal). A division ot the Molluscoida, 



comprising compound animals, such as the Sea-mat. Sometimes called 



Bryozoa. 



