GLOSSARY. 97 



O'vary (L. ovum, an egg). A gland which in animals secretes 

 the ova. In a plant, the part of the pistil which contains 

 the ovules. 



O'vicells (L. ovum, an egg). Dilatations of the body-wall in 

 the Polyzoa, in which the ova sometimes undergo the first 

 stages of their development. 



O'vicyst (L. ovum, an egg ; Gr. kustis, a bladder) The pouch 

 in which incubation takes place in some Ascidioida. 



O'viduct (L. ovum, an egg; duco, I lead). The tube which 

 leads from the ovary to the exterior, or from the ovary to 

 the uterus. 



Ovi'gerous frae'num (L. ovum, an egg ; gero, I bear; jranum, a 

 bridle). A triangular process projecting from the inner 

 wall on each side of the rudimentary abdomen in the 

 Cirripedia. 



Ovfparous (L. ovum, an egg; pario, I bring forth). Applied 

 to those animals which reproduce their kind by laying 

 eggs, which are wholly developed into the young animal 

 outside the body of the parent. 



Ovipo'sitor (L. ovum, an egg ; positor, one who founds, lays). 

 The tube along which the ova of insects pass while being 

 deposited. 



Ovotes'tis (L. ovum, an egg ; testis, a testicle). A gland which 

 in some Invertebrata secretes both male and female re- 

 productive elements. 



Ovovivi'parous (L. ovum, an egg ; vivo, I live ; pario, I bring 

 forth). Applied to those animals in which the develop- 

 ment of the young is completed within the body of the 

 parent, but quite unconnected with it. 



O'vula Nabothi (L. ovulum, a little egg). Small yellowish 

 follicles in the mucous membrane of the uterus. 



O'vule (L. ovulum, a little egg). The young seed in the ovary 

 of a plant. 



O'vum (L. an egg). The minute germ-cell from which, after 

 impregnation, the young of animals are developed. 



Oxida'tion. The chemical union of substances with oxygen. 



Ox'ygen (Gr. oxus, sharp, acid ; gennao, I produce). A 

 gaseous non-metallic element, existing largely in air and 

 water, and a supporter of life and combustion ; so named 

 because its presence was at one time erroneously supposed 

 to be necessary for the production of an acid. 



Ox'ygenate. To charge with oxygen. 



