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GLOSSARY 



ogous chromosomes which nifluence 

 "alternative" characters. 

 Al'ler-gy (Gr. all, ergij, ergon, work). A 

 condition in which substances that are 

 normally harmless cause a marked hy- 

 persensitivity or reaction. 

 Al-ve'o-lus (L. alveus, pit). A small cavity, 

 such as the alveoli of the lungs or the 

 socket of a tooth. 

 A-moe'boid (Gr. amoebe, change). Cell 

 movements resembling those of the 

 amoeba. 

 A-mi'no ac'id (from amine NHo). An or- 

 ganic compound resulting from pro- 

 tein breakdown; it must contain at 

 least one amino group ( NHo ) and one 

 acid group (COOH). 

 Am'i-to"sis ( Gr. a, without; mitos, thread ) . 

 Direct nuclear division without forma- 

 tion of condensed chromosomes or 

 spindle fibers. 

 Am'ni-on (Gr. amnos, lamb). A transparent 

 membrane surrounding the embryos of 

 reptiles, birds, and mammals. 

 Am'ni-o"ta (L. amniotes). A group of ver- 

 tebrates possessing an amnion and an 

 allantois — reptiles, birds, and mam- 

 mals. 

 Am'phi-as"ter (Gr. amphi, both sides of; 

 aster, star). A figure formed by the 

 spindle fibers and the two asters in the 

 dividing cell. 

 Am-phib'i-a (Gr. amphi, of both kinds; bios, 

 life). Class of vertebrates including 

 frogs, toads, and salamanders which 

 usually spend their larval life in water 

 (water breathers) and their adult life 

 on land (air breathers). 

 Am'y-lop"sin (amylase) (L. amyl, starch; 

 Gr. tnjsin, to wear down). A carbo- 

 hydrate-splitting enzyme produced by 

 the pancreas. 

 An-ab'o-lism (Gr. ana, up; bole, stroke). 



Constructive metabolism. 

 Anaro-gous (Gr. ana, up; logos, ratio, pro- 

 portion ) . Body parts with similar func- 

 tions but usually genetically dissimilar. 

 An-am'ni-o"ta (Gr. a, not; amnion, inner 



membrane around the fetus). A group 

 of vertebrates without an amnion — 

 cyclostomes, fishes, and amphibia. 

 An'a-phase (Gr. ana, up; phasis, appear- 

 ance, aspect). A stage in mitosis fol- 

 lowing metaphase when chromosomes 

 migrate from the equatorial plate to 

 the poles of the cell. 

 A-nas'to-mo"sis (Gr. ana, up; stoma, 

 mouth). The union of two or more 

 blood vessels, nerves, or other struc- 

 tiires. 

 A-nat'o-my (Gr. ana, up; temnien, to cut). 

 The study of the structure of animals 

 and plants. 

 An-nel'i-da ( L. annulus, ring; Gr. eidos, re- 

 semblance). A phylum of animals. 

 An-ten'na (L. a sailyard). Tactile sense or- 

 gans on the heads of arthropods. 

 An-ten'nules (L. diminutive of antenna). 

 Tactile sense organs located near the 

 antenna of many arthropods. 

 An-te'ri-or (L. foremost). Toward the head 



end of an animal. 

 An"ti-bod'y (Gr. anti, against; M.E. hodi, 

 body). A substance produced in the 

 body as a result of the presence of a 

 foreign body ( antigen ) . 

 An'ti-gen (Gr. anti, against; genes, born). 

 A substance which, when introduced 

 into the body, stimulates the produc- 

 tion of antibodies. 

 An'ti-tox"in (Gr. anti, against; L. toxicum, 

 poison ) . A substance in the body fluids 

 naturally occurring or induced which 

 neutralizes specific poisons or toxins. 

 A'nus ( L. ring ) . The exit of the alimentary 



canal opposite the mouth. 

 A-or'ta (Gr. aorte, the great artery). The 

 large artery carrying blood away from 

 the heart. 

 Ap'er-ture (L. aperire, to uncover). An 



opening. 

 Ap'i-cal (L. apex, summit). The top or 



apex. 

 Ap-pend'age (L. ad, to; pendere, to hang). 

 A part of the body that extends some 

 distance, such as an arm or leg. 



