8o4 



PATTERNS AND PROBLEMS OF DEVELOPMENT 



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

 ternal factors in liverwort gemmae, 430; 

 in relation to cleavage, chap, xiv, 630, 

 679; of hypotrichous protozoa, 617; in 

 hydrozoan budding, 635; visible evidence 

 of, in animal eggs, 657; embryonic, 672; 

 origin and nature of, 675; in meroblastic 

 vertebrate embryos, 687; in mammalian 

 embryo, 689 



Double assurance: definition of, 500; physio- 

 logical significance of, 501 



Drosophila, difTerential ovarian dye reduction 

 in, 144, 671, 677 



Dugesia, synonomy of, 41, footnote 7. See also 

 Planarians 



Dyes: differential staining by, 63; toxic 

 effects of, 65, 91, III, 125, 732; differential 

 reduction and oxidation of, 67, 90, 94, 

 no, 119, 124, 133, 134, 137, 143, 144, 156, 

 159, 162, 563, 662, 671, 732, 740; local 

 staining by, 438, 447; induction by, 478 



Ear: developmental field of amphibian, 288; 

 induction and determination of amphibi- 

 an, 496 



Earthworm: physiological gradients in, 121, 

 1 23; cephalic regeneration and old nervous 

 system of, 339 



Ectodermization: in echinoderm exogastrula, 

 227, 235, 239; by sodium thiocyanate, 243 



Electric current, determination of pattern by, 

 421, 424 



Electric potential : in relation to developmen- 

 tal pattern in general, 77; origin of, in or- 

 ganisms, 78; gradients in plants, 88; gra- 

 dient in sponge, 96; gradients in hydroids, 

 102; gradients in annelids, 127; gradients 

 in fish embryo, 151 



Emancipation: of parts from whole, 713; 

 limitations of, 713, 714 



Entelechy, 291, 645, 703 



Entodermization: in echinoderm exogastrula, 

 221, 223, 225, 228, 232, 233, 238; by im- 

 planted sea-urchin micromeres, 440 



Entomostraca: cleavage of, 574; centrifuged 

 eggs of, 586 



Evocation: and individuation in induction, 

 475; as activation, 479 



Exogastrula: of echinoderms as differential 

 modification, 221, 222, 233; agents pro- 

 ducing, 221, 232; entodermization in echi- 

 noderm, 221, 223, 225, 228, 232, 233, 238; 

 forms of echinoid, 223, 226; radial forms 

 of, 225, 228, 231; ectodermization in echi- 

 noderm, 227, 235, 239; development of 

 echinoderm, 227; of Patiria, 231; recon- 

 stitution in echinoderm, 236, 241; scale of 

 organization in echinoderm, 237; bipolar 

 forms of, 244, 443; amphibian, 463, 464; 

 annelid, 559 



Explantation: definition of, 83; of parts of 

 amphibian embryo, 462, 471, 526; of parts 

 of chick embryo, 533, 535 



Eye: in relation to field, 282, 531; induction 

 of parts of, 495; reconstitution in embry- 

 onic amphibian, 527; chick potency field 

 of, 531, 534 



Field, developmental: value and implication 

 of concept of, 276, 281; relation of gra- 

 dients to, 277; potency and differentiation 

 in, 277, 288; as gradient system, 278; in 

 reconstitution, 278; dominance in, 278; in 

 Corymorpha, 279; relation of metabolism 

 to, 279; of vertebrate eye, 282, 531, 534; of 

 amphibian limb, 285, 293; of amphibian 

 ear, 288; of balancer, 289; boundaries of, 

 290; of host in relation to induction, 474, 

 476, 483; of different parts in chick em- 

 bryo, 528, 531, 532, 533, 534 



Fir, electric-potential gradients in, 78 



Fishes: embryonic differential susceptibility 

 of, 147, 149, 256; reversible heart beat in, 

 329; formal developmental pattern of tele- 

 ost, 450; embryonic cell movements in 

 teleost, 451; induction in, 481; extra- 

 embryonic inductors in, 482; reconstitu- 

 tion of isolated blastomeres of, 521; em- 

 bryonic dorsiventrality of, 688 



Fission: in general, 13; in unicellular forms, 

 23, 24, 25; in metazoa, 26; in planarian, 

 26, 43, 321; in Stenosiomum, 27, 323, 399; 

 in annelids, 324; in Paramecium, 324; in 

 Fonticola, 325; regression of zones of, 398; 

 in Sporozoa, 604; asymmetry in protozo- 

 an, 617 



Fonticola: reconstitution in, 45; fragmenta- 

 tion in, 325 



Formative cells: in relation to differentiation 

 and dedifterentiation, 295, 301, 340; neo- 

 blasts as, 301 



Formative substances: in Acetabitlaria, 32, 

 362; do they exist? 292, 597; in echinoderm 

 development, 437; in spiral cleavage, 552, 

 558, 561; in ascidian development, 579 



Fragmentation: in planarians, 13, 325; in ne- 

 merteans and annelids, 13, 26, 326 



Fiicus, egg and early stage: original polarity 

 of, 86, 423; gradients in, 87; experimental 

 determination of polarity in, 423 



Fiindulus: embryonic differential susceptibili- 

 ty of, 149; embryonic differential inhibi- 

 tion in, 256; embryonic reconstitution of, 

 521, 523 



Fusion: of sponge larvae, 540; of planulae, 

 540; of nemertean cleavage stages, 540; of 

 A scar is eggs, 541; in sea-urchin develop- 

 ment, 541; of ascidian cleavage stages, 

 541 ; of amphibian two-cell stages, 542 



