GLOSSARY 607 



reflex action. An action involving one or more reflex arcs. 



regeneration (r6 j6n er a' shtin). The replacement of lost parts. 



renal (re' nal). Pertaining to the kidney. 



rennin (r6n' In). An enzyme produced in the stomach of mammals which coagulates 



the proteins in milk. 

 reproduction (re pro dtik' shtin). The production of a new organism by an older one. 

 respiration (r6s pi ra' shtin). The exchange of oxygen and carbon dioxide between 



an organism and its environment, or between the blood and different tissues. 

 response (re sp6ns'). An action on the part of an organism caused by a stimulus. 

 resting cell. A cell not undergoing division. 



rete (re' te). A network, diminutive reticulum (re tik' tl Itim); adj., reticular, 

 retina (rgf I na). The receptor cells of the eye; adj., retinal, 

 retractile (r6 trak' til). Capable of being withdrawn. 

 retro- (r6t' ro). L.; backward, 

 retrogression (r6t ro gr6sh' tin). The going backward by an animal during its 



development to a condition characterizing animals lower in the scale of life. 

 reversion (re vur' shtin). The reappearance of an ancestral character after a lapse 



of several generations. 

 rhabd (ribd). G.; rod. 

 rheotropism (re 6t' ro piz'm). A response by an organism to stimulation by a current 



of air or water; adj., rheotropic (re 6 tr6p' Ik). 

 rhiz (riz). G.; root, 

 rhjmcho (rin' ko). G.; snout. 



rhythmicity (rith mis' I tl). Variations repeated at regular inter^^als. 

 roe. The eggs of fishes. 



Ross, Sir Ronald. English physician; 1857-1932. 

 rota (ro' ta). L.; wheel. 



Saliva (sa li' va). The secretion of the salivary glands. 



sapro (sftp' r6). G.; decayed, rotten. 



saprophytic (sSp ro fit' Ik). Securing nourishment from the products of organic 



decomposition. 

 sarco (sar' ko). G.; flesh. 



sarcode (sar' kod). The term first applied to protoplasm by Dujardin. 

 sarcolemma (sar ko lem' a). The delicate membrane about a cross-striated muscle 



fiber. 

 sarcoplasm (sar' k6 plSz'm). The protoplasm of a striated muscle fiber outside the 



sarcostyles (sar' k6 stils), or longitudinal fibrils. 

 scaph (skfif). G. ; something hollow, boat. 



Schleiden (shll' d6n), Matthias J. German botanist; 1804-1881. 

 Schultze (shool' tse), Max J. S. German biologist; 1825-1874. 

 Schwann (shvan), Theodor. German zoologist; 1810-1882. 

 Sclater (skla' ter), PhUip L. English zoologist, 1829-1913. 

 scler (skl6r). G.;hard. 



sclerotic (skl6r 6t' Ik). The outer dense fibrous coat of the vertebrate eye. 

 scolex (sko' I6ks). The attached end or head of a tapeworm, 

 scut (skiit). L.; shield. 

 scute (skut). A ventral scale of a snake which is placed transversely and extends from 



one side of the body to the other, 

 scyph (skTf). G.; cup. 



scyphistoma (si fis' to ma). An attached polyp-like stage in a scyphozoan. 

 sebaceous (s6 ba' shtis). A term applied to oil glands connected with the hairs of 



mammals. 



