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GLOSSARY OF IMPORTANT TERMS 



Reproduction (re'pro duk'shwn) : the 

 process by which organisms produce 

 offspring. In asexual reproduction 

 a new organism is formed by the 

 separation of a cell or cells from a 

 single parent ; in sexual reproduc- 

 tion two cells from two plants or 

 two animals of different sexes come 

 together to form a new individual. 



Respiration (res'pi ra'sMn) : taking 

 in oxygen and giving out of prod- 

 ucts formed by oxidation by living 

 cells. 



Resuscitation (re stis'i ta'shftn) : re- 

 vival from unconsciousness. 



Retina (ret'i no) : the coat of the eye 

 in which the optic nerve fibers 

 terminate. 

 '* Rhizoid (ri'zoid) : one of the root- 

 like bodies in fungi and some other 

 plants. 



Rodents : gnawing mammals. 



Root hairs : epidermal cells elongated 

 from the root. 



Ruminant (roo'mi ndnt) : an animal 

 that chews a cud. 



Saliva (sd li'vd) : the secretion of the 



salivary glands. 

 Saprophyte (sap'ro fit) : an organism 



which derives its nourishment from 



dead organic matter, as a mold or a 



mushroom. 

 Sclerotic coat (side rot'ik) : the outer 



coat of the eye. 

 Scurvy : disease caused by lack of a 



vitamin. 

 Secretin (se kre'tin) : a hormone 



which causes the pancreas to give 



out its digestive fluid. 

 Secretion (se kre'sMn) : material 



formed by the activity of glands. 

 Seed: a structure formed in a fruit 



as a result of the fertilization of the 



egg cell. 

 Segment: one of a number of serial 



divisions of an animal's body or of 



an organ. 

 Self-pollination : shedding pollen 



directly on the stigma of the same 



flower. 

 Sensory (sen'so ri) : having direct con- 

 nection with any part of the seat of 



sensation. 

 Sepal (se'pal) : a leaflike part of the 



calyx or outer circle of parts in a 

 flower. 



Serum (se'rwm) : the liquid part of 

 the blood plasma. 



Setae (se'te) : bristles used for locomo- 

 tion in earthworms and other ani- 

 mals. 



Sexual (sgk'shu dl) : pertaining to or 

 having sex. 



Siphon (si'fon) : a tube through 

 which water may pass into and out 

 from the mantle cavity of a mollusk. 



Species (spe'shez) : the smallest group 

 of organisms having characteristics 

 in common that make them differ- 

 ent from all other organisms. 



Sperm cell: the male sex cell or 

 gamete. 



Spermatophyta (spur'md tof'i td) : 

 phylum which contains the seed- 

 producing plants. 



Spinal cord : a cord of nervous tissue 

 lying in the vertebral column. 



Spiracles (splr'd k'ls) : breathing holes 

 in the abdomen in insects. 



Spirillum (spl rlT&m) : a spiral form of 

 bacteria. 



Spleen (splen) : ductless, glandlike 

 organ near the stomach. 



Spongy tissue : a layer of loosely 

 placed cells in the leaf. 



Sporangium (spo ran'ji um) : a sac 

 containing spores. 



Spore (spor) : a reproductive cell 

 capable of growing into a mature 

 organism. It may be produced 

 sexually or asexually. 



Sporophyte (spo'ro fit) : spore-bearing 

 part of a plant. 



Stamen (sta'men) : an organ of the 

 flower in which pollen is formed. 



Staminate : having stamens but no 

 pistils. 



Statocyst (stat'6 slst) : semi-organs or 

 balancing pits, formed in crusta- 

 ceans and some other animals. 



Sterilize (ster'I Hz) : to destroy bac- 

 teria and other organisms, usually 

 by heating. 



Stigma (stig'md) : the part of a pistil 

 which receives the pollen grains. 



Stimulant (stim'ti ldnt) : a substance 

 which causes temporary activity of 

 nerve or muscle. 



Stimulus (stim'ti I&s) : an agent which 



