4 o8 GLOSSARY. 



OTODUS (Gr. ota, ears; odous, tooth). An extinct genus of 



Sharks. 

 OUDENODON (Gr. ouden, none; odous, tooth). A genus of Dicy- 



nodont Reptiles. 

 OVIBOS (Lat. ovis, sheep; bos, ox). The genus comprising the 



Musk-ox. 



PACHYDERM ATA (Gr. pachus, thick; derma, skin). An old Mam- 

 malian order constituted by Cuvier for the reception of the 

 Rhinoceros, Hippopotamus, Elephant, etc. 



PALE ASTER (Gr. palaios, ancient; aster, star). An extinct 

 genus of Star-fishes. 



PALEOCARIS (Gr. palaios, ancient; karis, shrimp). An extinct 

 genus of Decapod Crustaceans. 



PALEOLITHIC (Gr. palaios, ancient; lithos, stone). Applied to 

 the rude stone implements of the earliest known races of 

 men, to the men who made these implements, or to the period 

 at which they were made. 



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

 science of fossil remains or of extinct organized beings. 



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

 genus of Snakes. 



PALEOSAURUS (Gr. palaios, ancient; saura, lizard). A genus 

 of Thecodont Reptiles. 



PALEOTHERIDE (Gr. palaios, ancient; therion, beast). A group of 

 Tertiary Ungulates. 



PALEOZOIC (Gr. palaios, ancient; and zoe, life). Applied to 

 the oldest of the great geological epochs. 



PARADOXIDES (Lat. paradoxus, marvellous). A genus of Trilo- 

 bites. 



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

 pansion of the integument by which Bats, Flying Squirrels, 

 and other animals support themselves 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 com- 

 prising the Scallops. 



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

 the chest. 



PENTACRINUS (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; trenia, aperture). A genus of 

 Blastoidea, so-named in allusion to the apertures at the sum- 

 mit of the calyx. 



PERENNIBRANCHIATA (Lat. perennis, perpetual ; Gr. brag chia, gill). 

 Applied to those Amphibia in which the gills are permanently 

 retained throughout life. 



PERISSODACTYLA (Gr. perissos, uneven; daktulos, finger). Ap- 

 plied to those Hoofed Quadrupeds (Ungulata) in which the 

 feet have an uneven number of toes. 



