GLOSSARY-INDEX 417 



reproduction, 5, 45, 140, 238, 318, rate of. 



reproductive cells, 267. 



reproductive organs, 163, 199. 



reproductive system of Amoeba, 58; of bacteria, 81; of earthworm, 163; 



of Eudorina, 264; of frog, 214; of Hydra, 146, 151; of malarial Plasmo- 



dium, 71; of Monocystis, 241; of Pandorina, 74; of Paramecium, 63; of 



Penicillium, 98; of Ulothrix, 93; of yeast, 78. 



respiration. The exchange of gases between organisms and their environ- 

 ment, 56, 138, 160, 225; explained, 209, 312. 

 reticular theory of protoplasm, 31. 

 reticulum. A network, 32. 

 retina. The sensitive part of the eye, 196, 197. 

 rhizoids. Delicate hairs attaching some plants, like mosses, to the soil, 



270. 



Ridnus communis, 103. 

 rigor mortis (Lat. rigor = stiff + mors = death). The stiffening that 



occurs after death, 

 rivalries of organisms, 382. 

 root cap. A protective covering of hard cells over the tips of growing 



roots, 113. 

 root hairs. Delicate, single-celled absorption hairs, on the tips of roots 



of plants, 113. 

 root pressure. The pressure of sap in roots that forces sap up the stem, 



127. 



root structure, 112. 



rudimentary organs. Organs only imperfectly developed, 

 rusts, 232. 

 Saccharomyces, 78. 

 saccule, 198. 



sacrum. The fused vertebrae between the hip bones, 

 salivary glands. Glands secreting saliva, 204. 

 saprophytes (Gr.sapros = rotten + phyton = a plant). Plants which live 



upon the dead bodies of other organisms, 227. 



sarcode. A name first given to the living contents of animal cells, 40. 

 scapula, 182. 

 SCHLEIDEN, 38. 

 SCHULTZE, 40. 



SCHWANN, 38. 



sciatic plexus. The network formed by the several spinal nerves which 



combine to form the sciatic nerve, 194. 

 sclerenchyma (Gr. scleros = hard + enchyma = infusion). Plant cells wifch 



thick, hard walls. 



