528 GLOSSARY 



Self Differentiation. Differentiation due chiefly to intrinsic 

 causes. 



Sensitivity. Capacity of receiving and responding to stimuli. 



Sex Chro'-mo-some. The "odd" or accessory chromosome 

 which is supposed to determine sex. 



Sex-limited. Any character which is found in one sex only. 



Sex-linked. Any character, the determiner of which is as- 

 sociated with the determiner of sex. 



Simplex Factors or Character. A condition where the de- 

 terminer for a character is derived from one parent only. 



Sin'-is-tral snail. A type of snail in which the shell coils 

 from base to apex in an anti-clockwise direction. 



So'-ma. The body as contrasted with the germ cells. 



So-mat'-ic. Pertaining to the body, as contrasted with "germi- 

 nal" pertaining to the germ cells. 



So'-ma-to-plasm. The body-plasm as contrasted with the 

 germ-plasm. 



So'-mite. A segment of the body of a segmented animal. 



Sper-ma'-to-cytes. The mother and grandmother cells of 

 spermatozoa. 



Sper-ma-to-gen'-e-sis. The development of a spermatozoon 

 from a primitive sex cell. 



Sper-ma-to-go'-ni-a. Primordial sperm cells. 



Sper-ma-to-zo'-on. The mature male sex cell. 



Spindle. The nuclear division figure. 



Spi'-reme. A coiled thread of chromatin which appears in the 

 nucleus at the beginning of division. 



Spi-ril'-la. A spiral type of bacteria. 



Sten'-tor. A ciliated protozoan. 



Ster-e-o-i -so-meres. Molecules having the same composition 

 but different properties dependent upon varying spatial 

 relations of their constituent atoms. 



Stim'-u-lus. Anything acting on an organism which calls 

 forth a response. 



Sty-e'-la. A genus of Ascidians. 



Sym'-me-try. The condition where opposite sides or poles are 

 alike; bilateral, having equivalent right and left sides. 



