840 Appendix 



Lamarckism (la -mark' izm), Lamarck's theory that acquired characters are 



inherited. 

 Lamella (la-mel'a) (L. lamella, small plate), structure made by small plates, 



as lamella of bone or layers of a cell wall. 

 Lanugo (la-nu'go) (L. lanugo, down), downy covering of fetus shed early in 



life. 

 Larva (lar'va) (L. larva, mask), active, immature stage of development (con- 

 trast with Pupa). 

 Larynx (lar'inks) (Gr. larynx, larynx), enlarged anterior end of trachea (wind- 

 pipe) which contains the vocal folds; present in vertebrates except birds. 

 Legume (leg' yum) (L. lego, to gather), family of plants in which the seed 



vessel is two-valved and having a linear arrangement of seeds, as beans, 



alfalfa, peas. 

 Lepidoptera (lep i -dop' ter a) (Gr. lepis, scale; ptera, wings), order of insects 



with scaly wings as moths, butterflies, etc. 

 Lethal factor (le'thal) (L. letum, death), genetic factor that brings premature 



death to the individual. 

 Leucocyte (lu' ko sit) (Gr. leukos, white; kytos, cell), colorless blood corpuscle. 

 Leucoplast (id) (lu' ko plast) (Gr. leukos, white; plastos, formed), colorless 



plastid. 

 Levator (le-va' ter) (L. lavare, to rise), a muscle to elevate a structure. 

 Lichen (li' ken) (Gr. leichen, lick), flat plant composed of a chlorophyll-bearing 



alga and a fungus living together symbiotically. 

 Life cycle, various stages of development to maturity. 

 Ligament (lig'ament) (L. ligare, to bind), band of connective tissue to bind one 



bone to another or a support for an organ. 

 Lignin (lig'nin) (L. lignum, wood), chemical substance related to cellulose, con- 

 stituting the essential part of woody tissue. 

 Linin (li' nin) (L. linum, thread), fine threadlike structure associated with the 



chromatin of the nucleus. 

 Linkage, inheritance of traits in groups because their genes are near each other 



(linked) in the same chromosome. 

 Lipase (li' pase) (Gr. lipos, fat), a fat-splitting enzyme. 

 Lipoid (li' poid), of fatty nature. 

 Locomotion (lo ko -mo' shun) (L. locos, place; motus, move), moving from one 



place to another. 

 Lumbar (lum' ber) (L. lumbus, loin), pertaining to the loins (posterior to ribs). 

 Lumen (lu'men) (L. lumen, cavity), space within an organ or tube. 

 Lycopsida (lai -kop' si da) (Gr. \ykos, wolf; opsis, appearance), subphylum to 



which the club mosses belong. 

 Lymph (limf) (L. lympha, liquid), the blood plasma and white blood corpuscles 



which have passed from the circulatory vessels and which surround tissues 



and cells. 

 Lysin (li' sin) (Gr. lysis, destroy), substance which destroys cells or tissues. 



M 



Macrogamete (mak ro ga met') Gr. makros, large; gamos, gamete), large female 

 gamete (sex cell) produced by an oiganism exhibiting heterogamy. 



