GLOSSARY 245 



PROTOPODITE. The first or basal division of an appendage of a crustacean. 



PSEUDOPODIUM. A temporary prolongation or protrusion of the proto- 

 plasm of amoeboid cells. 



QUARTAN MALARIA. Recurrent chill and fever on every fourth day. 

 Caused by Plasmodium malariae. 



RECEPTOR. The molecule in protoplasm with which a toxin or various 

 metabolic elements may unite. 



RECESSIVE. In heredity, a factor which, although present in a hetero- 

 zygous individual, remains undeveloped. 



REDUCTION. The halving of the number of chromosomes in the nucleus of 

 a germ cell during maturation. 



REGIONAL DIFFERENTIATION. Specialization of a part of the body not 

 duplicated in other parts. 



RHIZOID. Resembling a root. 



RHIZOME. An underground trunk or stem. 



ROTIFER. Minute multicellular animal with rings of powerful cilia; "wheel- 

 animalcule." 



SAPROPHYTIC. Food-taking by absorption or osmosis; applies to some 

 plant forms. 



SAPROZOIC. Same, applying to animal forms. 



SARCODE. A term proposed by Dujardin, replaced by term protoplasm. 



SCHIZOGONY. The process of asexual multiplication in certain types of 

 parasitic protozoa. 



SCOLEX. The "head" or attaching segment of a tape- worm. 



SEX-LINKED. Any character the factor of which is associated with the sex 

 determiner. 



SINUS. A cavity or hollow in tissues. 



SOMATIC PLASM. Protoplasm of the body organs and tissues as opposed to 

 the reproductive or germinal plasm. 



SOMATOBLAST. A particular cell in early development destined to give 

 rise to the ventral plate of the embryo. 



SORUS. One of the aggregates of spore cases on the fronds of ferns. 



SPERMATOGENESIS. The development of spermatozoa from the primitive 

 or primordial sex cells. 



SPERMATOPHORE. A special capsule, case or sheath containing spermatozoa. 



SPIRACLE. An aperture for admitting air. 



SPIREME. A coiled mass of chromatin in thread form at the beginning of 

 nuclear division. 



SPORANGIUM. The case or sac within which spores are produced. 



STEAPSIN. A fat-transforming enzyme. 



STEREOME. The woody elements which impart strength to vascular bundles 

 and other tissues of plants. 



STIMULUS. Anything acting on living matter which calls forth a response. 



STOMA. Mouth; a breathing pore in plant leaves. 



STOMODAEUM. The anterior part of the digestive tract formed by ingrowth 

 of ectoderm. 



SYMBIOSIS. Obligatory living together of two organisms for mutual benefit. 



