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. 

 - -SPERM ATOGENESIS. 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. 

 fp.iREME. 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. 



