GLOSSARY 459 



segments in annelids and to homologous partitions in the muscles 

 of higher animals. 



Septicemia. Disease in which the disease-producing bacteria are dis- 

 seminated throughout the body of the host. See Bacteremia. 



Serum, {a) The liquid portion of the blood after the removal of the 

 blood corpuscles and the clotting agents. 



{b) The serum as described in (a), containing antibodies for im- 

 munization or treatment of bacterial disease. 



Serum therapy. Treatment of disease by means of blood serums con- 

 taining antibodies. 



SiNTus vENosus. The first chamber that the blood enters in the heart of 

 fishes and Amphibia. 



Soma. A general term applied to all tissues exclusive of the germ cell. 



Somatic mesoderm. The outer sheet of mesoderm that in the embryo 

 immediately underlies the ectoderm and forms the outer lining of 

 the coelom. 



Somatic number. The number of chromosomes characteristic of the 

 nuclei of the tissue cells. 



SoRi. Crescentic shaped organs containing spores, located on the under 

 side of fern leaves. 



Special creation. The doctrine which holds that animals and plants 

 were created simultaneously by the creative effort of some super- 

 natural power. 



Species adaptations. Adaptive characters that are common to all mem- 

 bers of a species, inherited. 



Sperm. A cell produced by a male or by a male gonad which combines 

 with a cell from the female and initiates the development of a new 

 individual. 



Spermary. a sac-like protrusion on the body wall of hydra in which 

 the spermatozoa are developed. 



Spermatid. A stage in spermatogenesis resulting when the secondary 

 spermatocyte divides. Spermatids have the haploid number of 

 chromosomes. 



Spermatogenesis. The process of conversion of primordial male germ 

 cells into mature spermatozoa. 



Spermatogonia. Male germs cells in their primary condition while 

 undergoing multiplication by ordinary mitosis. 



Spermatozoon. The male germ cell of animals. 



