8io 



PATTERNS AND PROBLEMS OF DEVELOPMENT 



511; alteration of ventrodorsality in, 512; 

 fusions in development of, 541; centri- 

 fugedeggsof, 587; pressure, cleavage, and 

 development of, 590; development and 

 Ca-f ree sea water, 59 1 ; dispermy and poly- 

 spermy in, 593 ; symmetry and asymmetry 

 of, 677; embryonic skeleton-forming ma- 

 terial of, 677 

 Siphonophore, physiological gradients in, 104 

 Sodium thiocyanate, action of, on echinoderm 

 development, 243, 244 



Spermatozoa: developmental patterns of, 

 621; origin of polarity in, 624, 625, 627; 

 differentiation and molecular pattern in, 

 630 

 Spermatozoids of plants, developmental pat- 

 terns of, 618 

 Spina bifida: as differential inhibition, 261; 



in chick development, 266 

 Spirostomum, differential dye reduction and 



susceptibility in, 94 

 Spirotrichonvnipha, spiral asymmetry in, 617, 



628 

 Sponges: physiological gradients in, 96; cell 

 and larval aggregates of, 418; origin of 

 pattern in gemmules of, 636 

 Spores: as material for developmental physi- 

 ology, 12; origins of pattern in plant, 599; 

 asymmetry of plant, 601; patterns of cni- 

 dosporidian, 607; of Noctiluca, 615 

 Sporozoa, origins of pattern in, 604, 605, 606, 



607 

 Starfish: physiological gradient in oocyte, 

 egg and early stages of, 130, 134, 739; dif- 

 ferential inhibition in, 212, 219; differen- 

 tial conditioning and recovery in, 216; dif- 

 ferential modification of coelom in, 219; 

 exogastrulation in, 230; egg section and 

 pattern in, 376; polar body position in, 

 661; symmetry and asymmetry in, 677 

 Stenostomum: fission in, 27, 323; differential 

 dye reduction and susceptibiUty in, 117; 

 destruction of zooids in, 399 

 Stolons: in differentially inhibited planulae, 

 169, 426; replacement of hydranths by, 

 172; of Tubularia, 314; of Corymorpha, 

 316; experimental localization of, in Cory- 

 morpha, 414 

 Strongylocentrotiis: differential developmental 

 modification in, 202; exogastrulation in, 

 226; egg section and pattern in, 376. See 

 also Sea urchin 

 Stylochus, physiological gradients in, 117 

 Substitution: definition of, 30; in plants, 32. 

 See also Reconstitution 



Suctoria: budding and pattern of, 609, 610, 

 613; "embryos" or larvae of, 609, 610, 613; 

 larval and parental pattern in, 613 



Sulphydryl : gradient in plant vegetative tips, 

 89; in amphibian embryo, 157 



Susceptibility, differential: aspects and sig- 

 nificance of, 70, 166; patterns of, 71, 735, 

 737, 743; of algae, 86; of Amoeba, 90; of 

 Paramecium, 92; of other ciliate protozoa, 

 94; of Phialidium, 96, 166; of other hy- 

 droids, 103, 104, 170, 172; of a siphono- 

 phore, 104; of ctenophores, 106; of planar- 

 ians, 112, 175; of polychete annelids, 120; 

 of oligochete annelids, 121, 126; of echino- 

 derm eggs and embryos, 131, 134, 140, 

 chap, vi, 739, 742; of mollusk embryos, 

 248; of insect embryo, 144, 250, 518; of 

 lamprey embryo, 147; of teleost embryos, 

 149, 256; of frog embryo, 152, 258, 743; 

 of chick embryo, 162, 265; Ranzi's inter- 

 pretation of, 249; of ascidian embryo, 

 250; in vertebrate development, 254, 394, 

 743; of amphibian dorsal lip region, 263; 

 of mammalian embryo, 266; in diatoma- 

 ceous pseudothallus, 641. See also Condi- 

 tioning, differential; Gradients, physi- 

 ological; Inhibition, differential; Pattern, 

 developmental; Recovery, differential; 

 Tolerance, differential 



Symmetry: radial in adventitious plant buds, 

 18; in buds in general, 20, 104, 633; of a 

 siphonophore, 104; radial, in differentially 

 inhibited echinoderm larvae, 208, 215; 

 radial in echinoderm exogastrulae, 225, 

 228, 231; bilateral of amphibian and chick 

 eye field, 282, 531, 534; in Harena^tis re- 

 constitution, 336; in reconstitution gener- 

 ally, 338; new radial, 359, 370; in relation 

 to light in plants, 430; in relation to cleav- 

 age, chap, xiv, 679; origin and nature of 

 embryonic, 672; different origins of radial, 

 674; patterns of echinoderm, 677; protein 

 configuration as basis of, 697; concentra- 

 tion gradients in, 700. See also Asym- 

 metry; Dorsiventrality; Pattern, develop- 

 mental; Ventrodorsality 



Taittogolahnts, embryonic differential suscep- 

 tibility in, 149 



Tolerance, differential: in general, 72, 166; 

 in planarians, 114; in Chaetoplerus, 120; 

 in echinoderm development, 204, 218. See 

 also Conditioning, differential 



Triton: differential dye reduction in embryos 

 of, 156; ligatured eggs of, 266, 524; neural 

 induction in, 455; lens development in, 

 489, 492; otic induction in, 496; branchial 

 induction in, 500. See also Amphibian de- 

 velopment; Amphibian dorsal inductor 



Triliirus: differential dye reduction in em- 

 bryos of, 157; temperature gradient and 

 development of, 463 ; lens induction in, 492 



Tubifex: embryonic differential susceptibility 



