GLOSSARY. 677 



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

 (See Omasum.) 



PSEUDEMBRYO (Gr. pseudos, falsity ; cmbruon, 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. 



PSEUDOH^MAL (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 Rhizoftoda 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; zndpous, 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. 



POLMOGASTEROPODA (= Pulmonifera). 



PULMONARIA. A division of Arachnida which breathe by means of pulmo- 

 nary sacs. 



PULMONATE. Possessing lungs. 



PULMONIFERA (Lat. pulmo, a lung ; and fero, 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.' puloros, a gatekeeper). The valvular aperture between the 

 stomach and the intestine. 



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



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

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



RADIATA (Lat. radius, a ray). Formerly applied to a large number of animals 



which are now placed in separate sub-kingdoms (e.g., the Ccdenterata, the 



Echinodermata, the Infusoria, &c.) 



RADIOLARIA (Lat. radius, a ray). A division of Protozoa. 

 RADIUS (Lat. a spoke or ray). The innermost of the two bones of the fore- 

 arm of the higher Vertebrates. It carries the thumb, when present, and 



corresponds with the tibia of the hind-limb. 

 RAHUS (Lat. a branch). Applied to each half or branch of the lower jaw or 



mandible of Vertebrates. 



RAPTORES (Lat. rapto, I plunder). The order of the Birds of Prey. 

 RASORES (Lat. rado, I scratch). The order of the Scratching Birds (Fowls, 



Pigeons, &c). 

 RATITJE (Lat. rates, a raft). Applied by Huxley to the Cursorial Birds, which 



do not fly, and have therefore a raft-like sternum without any medium 



keel. 

 RECTUM (Lat. rectus, straight). The terminal portion of the intestinal canal, 



opening at the surface of the body at the anus. 

 REPTILIA (Lat. repto, I crawl). The class of the Vertebrata comprising the 



Tortoises, Snakes, Lizards, Crocodiles, &c. 

 RETICULARIA (Lat. reticulitm,, a net). Employed by Dr Carpenter to desig- 



