GLOSSARY, 615 



Neuters. —Imperfectly developed females of certain social insects 

 (such as Ants and Bees), which perform all the labors of the 

 community. Hence they are also called workers. 



Ocelli. — The simple eyes or stemmata of Insects, usually situated 

 on the crown of the head between the great compound eyes. 



CEsoPHAGUS.— The gullet. 



Oolitic. — A great series of secondary rocks, so called from the 

 texture of some of its members, which appear to be made up of 

 a mass of small egg-like calcareous bodies. 



Operculum. — A calcareous plate employed by many Mollusca to 

 close the aperture of their shell. The opercular valves of Cirri- 

 pedes are those which close the aperture of the shell. 



Orbit. — The bony cavity for the reception of the eye. 



Organism. — An organized being, whether plant or animal. 



Orthospermous. — A term applied to those fruits of the Umbelliferae 

 which have the seed straight. 



Osculant. — Forms or groups apparently intermediate between and 

 connecting other groups are said to be osculant. 



Ova. — Eggs. 



Ovarium or Ovary (in plants). — The lower part of the pistil or 

 female organ of the flower, containing the ovules or incipient 

 seeds; by growth after the other organs of the flower have 

 fallen, it usually becomes converted into the fruit. 



O VIGEROUS . — Egg-beari ng. 



Ovules (of plants). — The seeds in the earliest condition. 



Pachyderms. — A group of Mammalia, so called from their thick 



skins, and including the Elephant, Rhinocerous, Hippopotamus, 



etc. 

 Paleozoic. — The oldest system of fossiliferous rocks. 

 Palpi. — Jointed appendages to some of the organs of the mouth in 



Insects and Crustacea, 

 Papilionace^. — Anorder of Plants (see Leguminos^). — The flowers 



of these plants are called papilionaceous, or butterfly-like, from 



the fancied resemblance of the expanded superior petals to the 



wings of a butterfly. 

 Parasite. — An animal or plant living upon or in, and at the 



expense of, another organism. 

 Parthenogenesis. — The production of living organisms fromunim- 



pregnated eggs or seeds. 

 Pedunculated, — Supported upon a stem or stalk. The peduncu- 

 lated oak has its acorns borne upon a footstool. 

 Peloria or Pelorism. — The appearance of regularity of structure 



in the flowers of plants which normally bear irregular flowers. 

 Pelvis, — The bony arch to which the hind limbs of vertebrate 



animals are articulated. 

 Petals. — The leaves of the corolla, or second circle of organs in a 



flower. They are usually of delicate texture and brightly colored. 

 Phyllodineous, — Having flattened, leaf-like twigs or leaf-stalks 



instead of true leaves. 



