GLOSSARY. 383 



PENTACRimTE. (Gr. penta, five ; hrinos, hair.) A pedunculated star-fish with five 

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



Pergameneous. {l^a.t. pergamen, parchment.) Of the texture of parchment. 



Periostracum. (Gr. per?, around ; ostrakon, aheW.') 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. peritonalos, the covering of the abdomen. ) Restricted to the 

 lining membrane of that cavity. 



Peritrejia. ( Gr. peri, around ; trenia, 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. phrac/ma, a partition ; konos, a cone.) The chambered cone 

 of the shell of the Belemnite. 



Phytophagous. ( Gr. p/iwtora, a plant ; phago, 1 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 featlier, or provided with 

 fins. 



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

 called Uqtior sanguinis. 



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



Plexus. { Gr. pleko, I twine.) A bundle of nerves or vessel's 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. pleisfos, most; kainos, 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. pous, a. ioot; ophthahnos, 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; pous, a foot.) The class of jNIollusca in which 

 the organs of motion are shaped like wings. 



Puljiograde. (Lat. jou/mo, a lung; gradior, I walk.) The tribe of Medusa^, 

 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. pt/rum, a pear.) Pear-shaped. 



QuAnRiFiD. Cleft in four parts. 



