472 



SENESCENCE AND REJUVENESCENCE 



Reproduction, gametic; Zygogenic 

 egg. 



Embryo sac, development of, 320. See 

 also Gametophyte. 



Encystment: in Planaria velata, 131; 

 in relation to character of nutrition in 

 Planaria velata, 169; in relation to age 

 cycle, 255, 256; influence of envelope 

 in, 404. 



Endomixis: process of , 143 ; in relation to 

 age cycle, 143; in relation to conjuga- 

 tion, 379, 380. 



Entelechy, 9, 54. 



Enzymes: colloid character of, 25; re- 

 tardation of action of, 67, 184; stabil- 

 ity of substratum in relation to, 41. 



Epigenesis, 46. 



Equisetum, spermatozoid of, 334. 



Evolution: increase in physiological 

 stability of substratum during, 45, 

 53, 194, 267, 298, 304, 460; increase 

 in differentiation during, 53, 286; 

 limitation of dedifferentiation during, 

 57, 230, 267, 286; increase in degree 

 of individuation, during 227, 266, 304; 

 senescence and rejuvenescence in, 193; 

 course of, in plants, 241; appearance 

 of death during, 304; of length of life 

 and of death, 304; interpretation of, 

 from individual development, 463; 

 as a secular senescence of protoplasm, 

 464; possibility of control of, 464. 



Exhaustion: distinction between, and 

 fatigue, 297; distinction between, and 

 senility, 297; as cause of death, 302. 



Fasciola hepatica, oogenesis of, 340. 



Fatigue: nature of, 1 88, 297; distinction 

 between, and exhaustion, 297; mental, 

 297; in relation to senility in nerve 

 cell, 297. 



Fertilization: rejuvenescence in con- 

 nection with, 307, 434; prevention of 

 death by, 307, 404; absence of, in 

 apogamy in plants, 322; effect of, 403, 

 424; quiescent period following, 403; 

 metabolic rate in animal eggs after, 

 405, 413. See also Conjugation; 

 Gametes; Parthenogenesis; Partheno- 

 genic egg. 



Fission: act of, in Planaria dorotocephala, 

 1 24; prevention of, in Planaria doroto- 

 cephala, 125; in Stenostomum, 135; 

 in infusoria, 137; in consequence of 

 decreased metabolism, 232. 



Fission plane: in Stenostomum, 135; in 

 infusoria, 138. 



Flower: rate of oxidation in, 349, 374; 

 definition of, 368; differentiation of, 

 368, 373, 3755 origin fi 3 6 8; limited 



growth of, 368; transformation of, 

 into vegetative shoot, 376. See also 

 Flowering. 



Flowering: in relation to senescence, 368; 

 early, in cuttings from blooming plants, 

 369; influence of light on, 371; experi- 

 mental control of, 372; physiological 

 conditions of, 373; periodic repetition 

 f> 375J premature, 376. 



Fragmentation: in Planaria velata, 130; 

 in relation to character of nutrition, 

 169; in relation to age cycle, 255, 256, 

 259- 



Functional hypertrophy, 43. 



Fundulus heteroclitus: susceptibility dur- 

 ing early development of, 416; period 

 of developmental rejuvenescence in, 

 compared with that in Tautogolabrus, 

 417. 



Gamete formation: in algae and fungi, 

 316; in mosses and ferns, 318; in seed 

 plants, 320, 377; as a process of special- 

 ization, 322, 330; conditions of, in 

 lower plants in relation to age, 364; 

 conditions of, in mosses and ferns 

 in relation to age, 366; loss of capacity 

 for, 367, 370; conditions of, in seed 

 plants, 368; conditions of, in protozoa, 

 377; conditions of, in hydra, 383; con- 

 ditions of, in margelid medusa, 384; 

 conditions of, in planarians, 384; 

 conditions of, in parasitic flatworms, 

 387; conditions of, in other inverte- 

 brates, 388; conditions of, in verte- 

 brates, 388; premature, 389; in 

 trematode larvae, 395. See also 

 Gametes. 



Gametophyte: in relation to life cycle, 

 253; in mosses and ferns, 253, 366; 

 development of, in seed plants, 320, 

 377; omission of, 322, 408. 



Gametes: physiological condition of, 

 270, 460; morphological condition of, 

 270, 316, 333; theoretical significance 

 of origin of, 315; of algae and fungi, 

 316; of mosses and ferns, 318; in seed 

 plants, 320; origin of, in animals, 322; 

 differentiation of parthenogenic and 

 zygogenic, 343; metabolic rate in 

 development of, 349; motor activity 

 in male, 350; susceptibility of, 351; 

 physiological conditions of maturation 

 j n , 353; different specialization of, in 

 infusoria, 404. See also Fertiliza- 

 tion; Gamete formation; Germ path; 

 Germ plasm; Reproduction, gametic. 



Gemmules of sponges, in relation to age 

 cycle, 256, 259. 



