GLOSSARY. 307 



PROSCOLEX (Gr. pro, before; sJcolex, 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, pro, before; soma, body). The anterior part of the body. 



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

 of insects. 



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

 typical limb of a Crustacean. 



PROTOPHYTA (Gr. protos ; andphuton, plant). The lowest division of plants. 



PROTOPLASM (Gr. protos ; and plasso, I mould). The elementary basis of 

 organised tissues consisting of an albuminoid, coagulable body. Some- 

 times used synonymously for ' sarcode.' 



PROTOZOA (Gr. protos ; and zobn, animal). The lowest division of the ani- 

 mal kingdom. 



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

 extremity of a limb or of an organism. 



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

 an Echmoderm. 



PSEUDO-HAEMAL (Gr. pseudos ; false, 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-NAViCELLvE (Gr. pseudos, false ; and Navicula, a genus of Diatoms). 

 The embryonic forms of the Grcgarinidce, so called from their resem- 

 blance in shape to the Navicula. 



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

 substance which are put forth by the Rhizopoda 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 pous, foot). A class of the Mollusca, 

 which swim by means of fins attached near the head. 



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

 nary sacs. 



PULMONATE. Possessing lungs. 



PULMONIFERA (Lat. pidmo, a lung ; and fero, I carry). The division of 

 Mollusca which breathe by means of a pulmonary chamber. 



PULMOGASTEROPODA ( = Pulmonifera). 



PUPA (Lat. a doll). The stage, of an insect, immediately proceeding its 

 appearance in a perfect condition. In the pupa-stage it is usually quies- 

 cent when it is often called a ' chrysalis ' but it is sometimes active 

 when it is often called a ' nymph.' 



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



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

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

 terata, the Echinodcrmata, the Infusoria, &c.). 



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



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

 nate those Protozoa, such as the Foraminifera, in which the pseudopodia 

 run into one another and form a net-work. 



REVERSED. Applied to spiral univalves, in which the direction of the 

 spiral is the reverse of the normal ; i.e. sinistral. 



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