39O GLOSSARY. 



PALEONTOLOGY (Gr. palaios, ancient ; and logos, discourse). The science of 



fossil remains or of extinct organised beings. 

 PAL/EOPHIS (Gr. palaios, ancient ; ophis, serpent). An extinct genus of 



Snakes. 

 PAL.EOSAURUS (Gr. palaios, ancient ; saura, lizard). A genus of Thecodont 



Reptiles. 

 PAL^OTHERID^! (Gr. palaios, ancient ; ther, beast). A group of Tertiary 



Ungulates. 

 PAL/EOZOIC (Gr. palaios, ancient ; and zoe, life). Applied to the oldest of the 



great geological epochs. 



PARADOXIDES (Lat. paradoxus, marvellous). A genus of Trilobites. 

 PATAGIUM (Lat. the border of a dress). Applied to the expansion of the in- 

 tegument by which Bats, Flying Squirrels, and other animals support them- 

 selves in the air. 



PECOPTERIS (Gr. peko, I comb ; pteris, a fern). An extinct genus of Ferns. 

 PECTEN (Lat. a comb). The genus of Bivalve Molluscs comprising the 



Scallops. 



PECTORAL (Lat. pectus, chest). Connected with, or placed upon, the chest. 

 PKNTACRINUS (Gr. penta, five ; krinon, lily). A genus of Crinoids in which 



the column is five-sided. 



PENTAMERUS (Gr. penta, five; meros, part). An extinct genus of Brachiopods. 

 PENTREMITES (Gr. penta, five ; trema, aperture). A genus of Blastoidea, so 



named in allusion to the apertures at the summit of the calyx. 

 PERENNIBRANCHIATA (Lat. perennis, perpetual ; Gr. bragchia,, gill). Applied 



to those Amphibia in which the gills are permanently retained throughout 



life. 

 PERISSODACTYLA (Gr. perissos, uneven ; daktulos, finger). Applied to those 



Hoofed Quadrupeds (Unyulata) in which the feet have an uneven number of 

 "toes. 



PETALOID. Shaped like the petal of a flower. 

 PHACOPS (Gr. plmM, a lentil ; ops, the eye). A genus of Trilobites. 

 PHALANGES (Gr. phalanx, a row). The small bones composing the digits of 



the higher Vertebrata. Normally each digit has three phalanges. 

 PHANEROGAMS (Gr. phaneros, visible ; gamos, marriage). Plants which have 



the organs of reproduction conspicuous, and which bear true flowers. 

 PHARYNGOBRANCHII (Gr. pharugx, pharynx; bragchia, gill). The order of 



Fishes comprising only the Laucelet. 

 PHASCOLOTHERIUM (Gr. phaskolos, a pouch ; therion, a beast). A genus of 



Oolitic Mammals. 

 PHRAGMACONE (Gr. phragma, a partition ; and konos, a cone). The chambered 



portion of the internal shell of a Belemnite. 



PHYLLOPODA (Gr. phullon, leaf; smApous, foot). An order of Crustacea. 

 PINNATE (Lat. pinna, a feather). Feather-shaped ; or possessing lateral pro- 

 cesses. 

 PINNIGRADA (Lat. pinna, a feather ; gradior, I walk). The group of Carniv- 



ora, comprising the Seals and Walruses, adapted for an aquatic life. Often 



called Pinnipedia,. 



PINNULE (Lat. dim. of pinna). The lateral processes of the arms of Crinoids. 

 PISCES (Lat. piscis, a fishV The class of Vertebrates comprising the Fishes. 

 PLACOID (Gr. plax, a plate ; eidos, form). Applied to the irregular bony 



plates, grains, or spines which are found in the skin of various fishes 



(Elasmobranchii). 

 PLAGIOSTOMI (Gr. playios, transverse ; stoma, mouth). The Sharks and Rays, 



in which the mouth is transverse, and is placed on the under surface of the 



head, 



PLATYCERAS (Gr. platus, broad ; keras, horn). A genus of Univalve Molluscs. 

 PLATYCRINUS (Gr. platus, broad ; krinon, lily). A genus of Crinoidea. 

 PLATYRHINA (Gr. platus, broad ; rhines, nostrils). A group of the Quadrumana. 

 PLATYSOMUS (Gr. platus, wide ; soma, body). A genus of Ganoid Fishes. 

 PLEISTOCENE (Gr. pleistos, most ; kainos, new). Often used as synonymous 



with "Post-Pliocene." 



