GLOSSARY 



of the eye containing the hght sensitive 

 receptors. 



Rh fac'tor (the Rhesus factor). A chemical 

 factor found in the blood of some indi- 

 viduals which has genetic significance. 



Rho-dop'sin (Gr. rhodon, rose; opsis, sight). 

 Visual purple. A substance found in the 

 retina and associated with vision. 



Ru-di-men'ta-ry (L. rtidis, unwrought, 

 rude). Imperfectly developed, or hav- 

 ing no function. 



Ru'mi-nant (L. nmien, throat). A group 

 of cud-chewing animals including the 

 cow, goat, and deer, which have a 

 stomach with four complete cavities. 



Sap'ro-zo"ic (Gr. sapros, rotten; zoion, liv- 

 ing being). Living on dead or decaying 

 organic matter. 

 Sar'co-lem"ma ( Gr. sarx, flesh; leinma, cov- 

 ering). The elastic sheath investing 

 each striated muscle fiber. 

 Sar'co-plasm (Gr. sarx, flesh; plasma, liq- 

 uid ) . The fluid protoplasmic matter of 

 striated muscles. 



Se-ba'ceous glands (L. sebum, tallow, 

 grease; L. glans, an acorn). Small skin 

 glands associated with hair follicles 

 which produce a waxy secretion for 

 lubrication of the skin. 



Se-cre'tin. A hormone produced by the in- 

 testinal wall which controls the secre- 

 tion of pancreatic juice. 



Se-cre'tion (L. secretio, from secernere, to 

 separate). The process of separating 

 various substances from the blood for 

 use by the organism; also the material 

 produced. 



Sed"en-tar-y (L. sedere, to sit). Perma- 

 nently attached form. 



Seg'ment (L. segmentum, a piece cut off). 

 A portion of a metameric organism. 



SelP-fer-ti-li-za'tion. Fertilization of an ego 

 by a sperm from the same individual. 



Se'men (L. serere, to sow). The sperm- 

 containing fluid of male animals. 



Sem'i-cir"cu-lar ca-nals" (L. semi, half; 



699 



cir cuius, circle). Canals in the inner 

 ear of the vertebrate which make up 

 an essential part of the sense organ of 

 equilibrium. 

 Sem'i-nal (L. semen, seed). Pertaining to 



the semen. 

 Sem'i-nal re-cep'ta-cles ( L. semen, seed; L. 

 recipere, to receive). Sac-like recepta- 

 cles in the female used for the storage 

 of sperm after copulation. 

 Sem'in-al ves'i-cles (L. semen, seed; L. 

 vesica, bladder). Sac-like structures in 

 the male used to store sperm. 

 Sem'i-nif"er-ous tu'bule (L. sernen, seed; 

 ferro, to carry; tubules, small tube). A 

 small duct used to convey seminal 

 fluid. 

 Sen'so-ry cell ( L. sensus, sense). Any recep- 

 tor cell. 

 Sep'tum (L. septum, partition). A partition 



between adjoining cavities. 

 Ser'i-al ho-moro-gy (L. series, join; Gr. 

 homos, same; logos, discourse). The 

 serial repetition of structures having 

 the same embryonic origin. 

 Se-rol'o-gy ( L. serum, liquid") . The study of 



serums and their actions. 

 Ses'sile (L. sedere, to sit). Attached, as 



opposed to free-living. 

 Se'tae (L. seta, bristle). Stiff brisde, as, for 

 example, the setae in the parapodia of 

 Neanthes. 

 Si'nus ( L. cavity). A cavity or hollow space. 

 Sorute (L. solvere, to loosen). The dis- 

 solved substance in a solution. 

 Sorvent (L. solvere, to loosen). The sub- 

 stance in which the solute is dissolved. 

 It is the continuous liquid portion of a 

 solution. 

 So'mite. A serial segment or metamere of 



an animal. 

 Spe'cies (L. appearance). A primary sub- 

 division of a genus. 

 Sperm ( Gr. seed ) . Male sex cell. 

 Sper'ma-ry, Male reproductive gland, testis. 

 Sper'ma-tid. The male germ cell just prior 



to the formation of the sperm. 

 Sper'ma-to-gen"e-sis (Gr. sperma, seed; 



