INDEX 



457 



Growth stimulating principle, 



postulated, 432-434 

 Growth zone, 



of athecate hydroids, 298 



sub-hypostonial, 426 



of hydra, 374 

 Gymnoblast, 297 



Habitat, Craspcdacustu, 317 

 H all me da, 



calcification by, 276 

 carbon fixation by, 276, 277 

 Halo zone, 339, 343, 344, 354, 357, 360 



ammonium bicarbonate of, 349 

 description of, 338 



preparation of halo zone water, 345 



Rachevsk>''s formulation for, 339, 340 



reinforced by group effect, 338 



varies with size of hydra, 338 

 Haploneme, 189 

 Head, of nematocvst tubule, 132, 134, 



135, 138, 140, 142 

 Heat, effect of, on hydra's food, 235 

 Heisenberg's principle, relation to sexual 



differentiation, 344 

 Hermatypic corals, 



carbon fixation in, 276, 277 



defined, 270 



distribution of, 270 



growth properties of, 270 



oxygen production of, 273 

 Heteroneme, 189 

 Histamine, 181 



distribution of, 180 

 Histology, general, 



of basal disk, 7 



of bud, 8 



of cnidoblast, 3 



of digestive cell, 4 



of ectodemi, 2 



of endoderm, 4 



of epithelio-muscular cell, 2 



of gland cells, 4 



of hydra, 1-49 



of hypostome, 7 



of interstitial cells, 2 



of mesoglea, 3 



of muscular system, 5 



of peduncle, 7 



of tentacle, 7 

 Histological studies, of regeneration, 409 

 Holotrich, 189 

 Homarine, 180 

 Hook, of nematocvst tubule, 133, 138. 



149 



Hoplotelic, 189 

 Host-synibiont relationships, 

 in A. elegantissima, 255-258 

 in C. viridissima, 254-263 

 in corals, 271 

 Human myocardium, aging of, 379 

 Human skin, aging of, 377, 378 

 Hydra, 



acid phosphatase of, 381-384 

 in pedal disk, 384, 385 

 in tentacles, 384 

 action potentials of, 75, 76 

 advantage of, 



as a laboratory animal, 203 

 for the study of cellular differentia- 

 tion, 337 ' 

 aging of, 373, 379 

 anatomical regions of, 1 

 budding of, 441-448 



chemical changes during, 441-448 

 stages of, 442 

 cellular attachments of, 51-66 

 culture of, 206 

 death of cells in, 379 

 digestion in, intracellular, 241 

 DNA/protein ratio of, 443, 445 

 epithelial layers of, 51, 52 

 ft^eding apparatus for, 235 

 feeding reflex of, 203-231 

 ganglion cell of, 72 

 genotypic constancy of, 203 

 growth factors of, 235-243, 425 

 growth on non-living diet, 234, 235, 



240 

 growth zone of, 374 

 growth rate of, 403 

 histochemical properties of, 379 

 histology of, 1-49 



hydroxyproline changes in regenera- 

 tion, 316 

 5-hydroxytroptamine of, 163 

 intercellular attachments of, 51 

 as a laboratory animal, 203 

 metabolic gradient of, 425 

 mesoglea of pedal disk, 177 

 mesogleal attachments of, 51 

 Microsporidia, infected with, 401, 402 

 mitosis in, 316 



nematocyst of, 10, 77-168, 187-202 

 nematocvst capsule, chemistrv of, 153- 



156 

 nematocyst toxin, chemistrv of, 156- 



168 

 nerve cells of, 69, 72 

 nervous system of, 69, 72 



