GLOSSARY. 595 



POLYPIDE. The separate zooid of a Polyzoon. 



POLYPIDOM. The dermal system of a colony of a Hydrozoon, or PolyzoSn. 



POLYPITE. The separate zooid of a Hydrozoon. 



POLYSTOME (Gr. polus, many ; and stoma, mouth). Having many mouths ; 



applied to the Acinetce amongst the Protozoa. 



POLYTHALAMOUS (Gr. polus ; and thalamos, chamber). Having many cham- 

 bers; applied to the shells of Foraminifera and Cephalopoda. 

 POLYZOA (Gr. polus ; and zoon, animal). A division of the Molluscoida, com- 

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

 POLYZOARIUM. The dermal system of the colony of a Polyzoon (= Poly- 



pidom). 



PORCELLANOUS. Of the texture of porcelain. 



PORIFERA (Lat. porus, a pore ; and Jero, I carry). Sometimes used to desig- 

 nate the Foraminifera, or the Sponges. 

 POST-ANAL. Situated behind the anus. 

 POST (ESOPHAGEAL. Situated behind the gullet. 

 POST-ORAL. Situated behind the mouth. 

 PR^I-MAXILL^E (see Interrnaxitlce). 

 PR^MOLARS (Lat. prce, before ; molares, the grinders). The molar teeth of 



Mammals which succeed the molars of the milk set of teeth. In man, the 



bicuspid teeth. 



PR^E-CESOPHAGEAL. Situated in front of the gullet. 

 PR^E-STERNUM. The anterior portion of the breast-bone, corresponding with 



the manubrium sterni of human anatomy, and extending as far as the point 



of articulation of the second rib. 

 PRESSIROSTRES (Lat. pressus, compressed; rostrum, beak). A group of the 



Grallatorial Birds. 

 PROBOSCIDEA (Lat. proboscis, the snout). The order of Mammals comprising 



the Elephants. 

 PROBOSCIS (Lat. or Gr. the snout). Applied to the spiral trunk of Lepidopter- 



ous Insects, to the projecting mouth of certain Crinoids, and to the central 



polypite in the Medusae. 

 PROCCELOUS (Gr. pro, front; Icoilos, hollow). Applied to vertebrae, the bodies 



of which are hollow or concave in front. 

 PROGLOTTIS (Gr. for the tip of the tongue). The generative segment or joint 



of a Tapeworm. 



PRO-LEGS. The false abdominal feet of Caterpillars. 

 PRONATION (Lat. pronus, lying on the face, prone). The act of turning the 



palm of the hand downwards. 

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



Molluscs. 

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



Tapeworm. 

 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 pous, foot). The basal segment of the 



typical limb of a Crustacean. 



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

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

 ganised tissues. Sometimes used synonymously for the "sarcode" of the 



Protozoa. 

 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. prommus, next). The slowly-growing, comparatively-fixed 



extremity of a limb or of an organism. 



