SUBJECT-INDEX. 



659 



ferentiation, I, 204; division of 

 labour, I, 207, 363-4, 367; func- 

 tional interdependence, I, 237-9, 

 240-2; autogenous development of 

 units in colonies, I, 364, 367-8, II, 

 620; belief in social evolution, I, 

 432; natural selection, I, 553, II, 

 532; integration and differentia- 

 tion, II, 378-9; effects of popula- 

 tion, II, 535-6; equilibration, II, 

 537. 



Soil, dependence of plant evolution 

 on, II, 402. 



Solarium jasminoidcs, organs of at- 

 tachment, II, 276. 



Solar system, autogenous develop- 

 ment illustrated by distribution 

 of forces in, I, 366. 



Sole, symmetry and location of 

 eyes, II, 205. 



Soma-plasm, Weismann's theory of 

 differentiation from germ-plasm, 

 I, 357, 622, 628-30, 633^4. 



Somites (see Segmentation). 



Special creation: and evolution, I, 

 412, 415, 431; improbabilities, I, 

 418-9, 430, 439, 554; inconceiva- 

 bility, I, 420, 429, 431, 554; of in- 

 dividuals and species, I, 421-4; 

 the implication of beneficence, I, 

 425-9; summary, I, 429, 554; Von 

 Baer's formula, I, 451-6; verte- 

 brate skeleton, II, 551, 556, 565. 



Species: adaptation and stability, I, 

 242; hereditary transmission, I, 

 301-4; variation in wild and culti- 

 vated, I, 323-5, 326, 693; ga mo- 

 genesis and life of, I, 347-9; phy- 

 siological units, I, 362, 364, 369- 

 71, 458, II, 613; indefiniteness, I, 

 389, 445, 572; special creation, I, 

 422-4; instability of homogeneous, 

 and differentiation of, I, 509-11, 

 515, 517-8, 550, 557; persistence 

 of, I, 516, 518, II, 10-11; natural 

 selection and equilibration, I, 

 543-8, 553, 557; non-adaptive char- 

 acters, I, 565; morbid products as 

 marks of, I, 567; migration and 

 isolation as causes of differentia- 

 tion, I, 568-9; increasing multi- 

 formity of aggregate, II, 396. 



Specific gravity, of organisms and 

 environment, I, 174, 177. 



(see Fertilization). 



Spermatozoa 



Sperm-cell 



Sphere: tendency of units to form, 



I, 15; the embryonic form, I, 177; 

 symmetry, II, 131. 



Spheroid, symmetry, II, 132. 



Spiders (see Arachnida). 



Spine (see Tcrtebrata). 



Sponge: structure and dynamic ele- 

 ment in life, I, 119; multicentral 

 development, I, 164; units and ag- 

 gregate, I, 185; reproductive tis- 

 sue, I, 283; integration, I, 586; II, 

 90, 383; physiological differentia- 

 tion, II, 300, 386; development 

 and genesis, 11,463; analogy from, 



II, 576. 



Spontaneous generation: and hete- 

 rogenesis, I, 270; and evolution, 

 I, 696-701, 703. 



Stag, horns and correlated struc- 

 tures, I, 567, 670, 676-7, 692. 



Stamens, and foliar homology, II, 

 44. 



Starches: properties, I, 11; trans- 

 formations, I, 66, 68, 69, 70, II, 

 593. 



Star-fishes (see Asteroidea). 



Statoblasts, of Plumatella, I, 277. 



Steenstrup, on " Alternate Genera- 

 tion," I, 592. 



Sterility (see Multiplication). 



Stickleback: ova, II, 454; bothrio- 

 cephalus in, II, 490. 



Stomach (see Alimentary canal). 



Stomata, distribution, II, 260-1. 



Straight line, and evolution hypoth- 

 esis, I, 433. 



Strain: compression and tension of, 



I, 151, II, 209-12; relation to 

 mass, I, 155-7; vegetal structure, 



II, 574-88, 592-6; origin of ver- 

 tebrate type, II, 600. 



Strawberry: multiaxial develop- 

 ment, I, 166; multiplication, II, 

 441. 



Strength, a vital attribute, I, 578. 



Structure: appliances for generat- 

 ing motion, I, 75-7; biological 

 classification, I, 125-7, 129; size 

 and organic, I, 137; growth and 

 complexity, I, 138, 145, 161; rela- 

 tion to environment, 1, 172-8, 195-6; 

 of unicellular organisms, I, 181-3; 



