470 GLOSSARY. 



NEUTERS, a name given to the working Bees, to distinguish 



them from the males and females of the hive. 

 NICTITATING MEMBRANE, that which is called the third eyelid 



in birds. 

 NUDIBRANCHIATA, an order of mollusks in which the gills are 



naked or exposed (as in Eolis, Fig. 164.) Lat. nudus, naked, 



branchiae, gills. 



OCELLI, little eyes. Lat. ocellus, a little eye. 

 (ESOPHAGUS, the gullet. 

 OLFACTORY, smelling, or having the sense of smell. Lat. 



olfacere, to smell. 

 OMNIVOROUS, eating food of every kind. Lat. omnis, all, and 



voro, I devour. 

 OPHIDIA, that order of reptiles under which all serpents are 



included. Gr. ophis, a snake. 

 ORGANIC, consisting of parts made to co-operate with each 



other, as in those which constitute the bodies of plants or 



animals. 

 ORGANIC REMAINS, the remains of animals or plants (organized 



bodies) found in a fossil state. 

 ORGANS, the parts or instruments by which certain objects are 



effected. Lat. organum, a machine or instrument. 

 ORTHOCE'RATITES, a name given to a group of large chambered 



fossil shells, which are straight and tapering. Gr. orthos, 



straight, and Jceras, a horn. 

 ORTHOP'TERA, an order of four-winged insects, in which the 



wings are longitudinally folded when at rest, as in the 

 . Cricket and Grasshopper. Gr. orthos, straight, and pleron, 



a wing. 

 OSSEOUS FISHES, those that have the skeleton of bone. Lat. 



05, a bone. 

 OTOLITES, the ear-bones of fishes. Gr. ous, otos, the ear. 



SviSAcTl rece P tacles for the e g s or ova " 



OVI'GEROUS VESICLES, the little bladders or cells in which the 



ova or germs of some Zoophytes are observed. Lat. ova, 



eggs, and gero, I bear or carry. 

 OVIPAROUS ANIMALS, those whose young are produced from 



eggs. Lat. ovum, an egg, and pario, 1 bring forth. 

 OVIPOSITOR, the instrument by which eggs are deposited. It 



is remarkable for its great length in some species of insects. 

 OVO-VIVIPAROUS ANIMALS are those in which the egg is rup- 

 tured in the act of deposition, and the young are brought 



forth alive. 

 OXYGEN, a gas which is one of the constituent parts of water, 



and of atmospheric air; it is essential to animal life. 

 PACHYDERMATA, an order of quadrupeds, including the Elephant, 



and other animals distinguished by having thick skins. 



Gr. pachys, thick; and derma, the skin or hide. 

 PALPI in insects, the organs popularly termed "feelers." Lat. 



palpwn, a gentle touch or pat. 



