550 GLOSSARY 



Hor'mones (Gr. hormaein, to excite): substances secreted directly into the blood in one 



part of the body which incite action in another part of the body. 

 Humor (Lat. humere, to be moist): the transparent liquids of the eyeball. 

 Hymenop'tera (Gr. hymen, a membrane; pteron, wing): an order of insects (including 



bees) with membranous wings. 

 Ichneu'mon (Gr. ichneuo, hung): a hymenopterous insect which lays its eggs on the 



larvae of other insects or in them; a helpful parasite. 

 Immu'nity (Lat. immunis, free from duty): the condition which prevents a person from 



contracting infectious diseases. 

 Incis'or (Lat. incido, cut into): a cutting tooth. 

 Insectiv'ora (Lat. insectum, insect; voro, to eat): order of insect-eating vertebrates, 



including moles. 

 Inser'tion (Lat. insertus, from in, in; sero, join): the place of attachment of a muscle. 

 Integ'ument (Lat. in, in; tego, cover): an outer covering or envelope, as the skin. 

 Intes'tine (Lat. intestinus, internal): the alimentary canal in vertebrates between the 



stomach and the anus. 

 I'ris (Gr. iris, rainbow): the colored portion of the eye. 

 Irritabil'ity (Lat. irritabilis, from irrito, excite): reaction to stimuli. 

 Joint (Lat. y««^o, join): meeting-place of two bones; an articulation. 

 Lep'idop'tera (Gr. lepis, scale; pteron, wing): the order of insects characterized by scaly 



wings, as moths and butterflies. 

 Leu'cocyte (Gr. leiikos, white; kutos, vessel): a white blood-corpuscle. 

 Lig'ament (Lat. ligare, to bind): a band of tissue binding one bone to another. 

 Lip'oid (Gr. lipos, fat; eikos, like): a substance found in the nervous system which is 



dissolved by anaesthetics or narcotics. 

 Locomo'tion (Lat. locus, place; motus from moveo, move): movement from one place to 



another. 

 Lymphat'ic (Lat. lympha, clear water): a vessel conveying lymph. 

 Mala'ria (Lat. malus, bad; a^T, air): a disease caused by parasitic protozoons which 



live in the mosquito, Anopheles, during part of their life history, and part in the 



blood of man to which they are transmitted only by the bite of this mosquito. 

 Mam'mary (Lat. mamma, breast) glands: the milk-secreting glands, characteristic of 



mammals. 

 Man'dible (Lat. mandere, to chew): the cutting part of the mouths of crustaceans. 

 Marsu'pials (Gr. marsipion, a little pouch): an order of mammals having a pouch in 



which the young are carried, as opossum, kangaroo. 

 Medus'a (Gr. medousa, the gorgon): a name given to the main free-swimming type of 



Coelenterate, the jelly-fish. 

 Mes'entery (Gr. mesas, middle; enteron, intestine): tissue which suspends the intestine 



from the dorsal wall of the abdomen. 

 Metamor'phosis (Gr. meta, beyond; morphe, form): a life history in which the organism 



passes through abrupt changes of form, as the butterfly, frog. 

 Mesotho'rax (Gr. mesos, middle; thorax, thorax): the middle section of the thorax of an 



insect. 

 Metab'olism (Gr. meta, beyond; ballein, to throw): the chemical processes which take 



place in a living organism. 

 Migra'tion (Lat. migro, move): moving from one locality to another, as birds, salmon. 



