GLOSSARY. 383 



Pentacrinite. (Gr. penta^ five ; krinos, hair.) A pedunculated star-fish with five 



rays : they are, for the most part, fiassil. 

 Pergameneous, (luat. pergamen, parchment.) Of the texture of parchment. 

 Periostracum. (Gr. peri, around ; ostrakon, shell.) The membrane analogous to 



scarf-skin, which covers shell. 

 Peristaltic. (Gr. peri ; stello, to range.) The vermicular contractions and motions 



of muscular canals, as the alimentary, the circulating, and generative tubes. 

 Peritoneal. ( Gr. peritonaios, the covering of the abdomen. ) Restricted to the 

 lining membrane of that cavity. 



Peritrema. (Gr. peri, around; trema, hole.) The raised margin which sur- 

 rounds the breathing holes of scorpions. 



Petiolate. (Lat. petiolus, a fruit stalk. ) Ducts supported or suspended by a 

 slender stalk. 



Pharynx. The dilated beginning of the gullet. 



Pharyngeal. Belonging to the pharynx. 



Phragmocone. ( Gr. j9^ra^ma, a partition ; ^owos, a cone.) The chambered cone 

 of the shell of the Belemnite. 



Phytophagous. ( Gr. phuton, a plant ; phago, I eat. ) Plant-eating animals. 



Pigmental. (Lat. pigmentum, paint.) The cells which secrete the coloured par- 

 ticles of the skin and eye, and the membrane formed by such cells. 



Pinnate. (Lat. pinna, a feather or fin.) Shaped like a feather, or provided with 

 fins. 



Plasma. The fluid part of the blood, in which the red corpuscles float : also 

 called liquor sanguinis. 



Plastron. The under part of the shell of the crab and tortoise. 



Plexus. ( Gr. pleko, I twine.) A bundle of nerves or vessels interwoven or 

 twined together. 



Pleiocene. (Gr. pleion, more; kainos, recent.) The tertiary strata, which are 

 more recent than the miocene, and in which the major part of the fossil testacea 

 belong to recent species. 



Pleistocene. (Gr. pleistos, most; kaitios, recent.) The newest of the tertiary 

 strata, which contains the largest proportion of living species of shells. 



Plic^. (Lat. plica, a fold.) Folds of membrane. 



Plumose. (Lat. pluma, a feather.) Feathery, or like a plume of feathers. 



Pneumatic. ( Gr. pneuma, breath.) Belonging to the air and air-breathing organs. 



Podophthalma. (Gr. pons, a foot; ophtJialmos, an eye.) The tribe of Crustacea 

 in which the eyes are supported upon stalks. 



Polygastria. (Gr. polus, many ; gaster, a stomach.) The class of infusorial ani- 

 malcules which have many assimilative sacs or stomachs. 



Polypi. (Gr. polus ; pons, a foot.) The class of radiated animals with many pre- 

 hensile organs radiating from around the mouth. 



Prolegs. The wart-like tubercles which represent legs on the hinder segment of 

 caterpillars. 



Prothorax. (Gr.pro, before, and thorax.) The first of the three segments which 

 constitute the thorax in insects. 



Psychical. ( Gr. psuche, the soul. ) Relating to the phenomena of the soul, and 

 to analogous phenomena in the lower animals, 



Pteropoda. ( Gr. pteron, a wing ; pons, a foot. ) The class of Mollusca in which 

 the organs of motion are shaped like wings. 



PuLMOGRADE. {luaX. pulmo, a lung; gradior, I walk.) The tribe of MeduScP, 

 which swim by contractions of the respiratory disc. 



PuLMONATA. (Lat. pulmo.) The order of Gasteropods that breathe by lungs. 



Pupa. ( From the Latin for a doll or little image. ) The passive state of an insect 

 immediately preceding the last. 



PupiPARous. (hat. pupa; pario, I produce. ) The insects that bring forth their 

 young in the pupa state. 



Pylorus. From the Greek. The aperture which leads from the stomach to the in- 

 testine. 



Pyriform. (Lat. pijrum, a pear.) Pear-shaped. 



Quadrifid. Cleft in four parts. 



