812 GLOSSARY. 



PROPODIUM (Gr. pro, before; pous, foot). The anterior part of the foot, in 

 Molluscs. 



PROSCOLEX (Gr. pro, before ; scolex, worm). The first embryonic stage of a 

 Tape- worm. 



PROSOBRANCHIATA (Gr. proson, in advance of; bragchia, a gill). A division 

 of Gasteropodous Molluscs in which the gills are situated in advance of the 

 heart. 



PROSOMA (Gr. IJTO, before ; soma, body). The anterior part of the body. 



PROTHORAX (Gr. pro; and thorax, chest). The anterior ring of the thorax of 

 insects. 



PROTOPHYTA (Gr. protos, first ; and phuton, plant). The lowest division of 

 plants. 



PROTOPLASM (Gr. protos; andplasso, I mould). The elementary basis of or- 

 ganised tissues. Used synonymously with the ' ' sarcode " of the Protozoa. 



PROTOPODITE (Gr. protos, first; and pous, foot). The basal segment of the 

 typical limb of a Crustacean. 



PROTOZOA (Gr. protos; and zoon, animal). The lowest division of the animal 

 kingdom. 



PROVENTRICULUS (Lat. pro, in front of; ventriculus, dim. of venter, belly). 

 The cardiac portion of the stomach of birds. 



PROXIMAL (Lat. proximus^ next). The slowly -growing, comparatively-fixed 

 extremity of a limb or of an organism. 



PSALTERIUM (Lat. a stringed instrument). The third stomach of Ruminants. 

 (See Omasum.) 



PSEUDEMBRYO (Gr. pseudos, falsity ;. embruon, embryo). The larval form of 

 an Echinoderm. 



PSEUDOBRANCHIA (Gr. pseudos, falsity; bragchia, gill). A supplementary 

 gill found in certain fishes, which receives arterialised blood only, and does 

 not, therefore, assist in respiration. 



PSEUDOILEMAL (Gr. pseudos, falsity ; and haima, blood). Applied to the vas- 

 cular system of Annelida. 



PSEUDO - HEARTS. Certain contractile cavities connected with the atrial 

 system of Brachiopoda, and long considered to be hearts. 



PSEUDO-NAVICELL^E (Gr. pseudos, false ; and Navicula, a genus of Diatoms). 

 The embryonic forms of the Gregarinidce, so called from their resemblance 

 in shape to the Navicula. 



PSEUDOPODIA (Gr. pseudos ; and pous, foot). The extensions of the body- 

 substance which are put forth by the Jthizopoda at will, and which serve 

 for locomotion and prehension. 



PSEUDOVA (Gr. pseudos; Lat. ovum, egg). The egg-like bodies from which 

 the young of the viviparous Aphis are produced. 



PTEROPODA (Gr. pteron, wing ; and^ows, foot). A class of the Mollusca which 

 swim by means of fins attached near the head. 



PTEROSAURIA (Gr. pteron, wing ; saura, lizard). An extinct order of reptiles. 



PUBIS (Lat. pubes, hair). The share-bone ; one of the bones which enter into 

 the composition of the pelvic arch of Vertebrates. 



PULMOGASTEROPODA (=Pulmonifera). 



PDLMONARIA. A division of A rachnida which breathe by means of pulmonary 

 sacs. 



PULMONATE. Possessing lungs. 



PULMONIFERA (Lat. pulmo, a lung; and/ero, I carry). The division of Mol- 

 lusca which breathe by means of a pulmonary chamber. 



PUPA (Lat. a doll). The stage of an insect immediately preceding its appear- 

 ance in a perfect condition. In the pupa-stage it is usually quiescent when 

 it is often called a " chrysalis ; " but it is sometimes active when it is often 

 called a "nymph." 



PYLORUS (Gr. paloros, a gatekeeper). The valvular aperture between the 

 stomach and the intestine. 



PYRIFORM (Lat. pyrus, a pear ; and forma, form). Pear-shaped. 



QUADRUMANA (Lat. quatuor, four; manus, hand). The order of Mammals 

 comprising the Apes, Monkeys, Baboons, Lemurs, &c. 



