Metastasis, 106
Principle of Connections, 107-8
Anatomy and Embryology, 108
Homology and Analogy, 108
Classes of Homology, 108-9, 266
Functional Attitude, 109, 110, 111
Embryological Criterion, 110, 167
Homological and Teleological Compoundedness, 110-1
Vegetative Repetition of Parts, 111, 286
Unity of Plan as Conservative Principle, 112
Influence on Darwin, 234, 235, 238
Evolution, 244

PACKARD, 361

Palaeontological Record, 357-61
Absence of connecting forms, 357-9
Biogenetic Law, 359
Phyletic Series, 359-61

Palaeontological Succession--
Cuvier, 43
E. Geoffroy, 67
L. Agassiz, 230, 255
C. Darwin, 231
Milne-Edwards, 245
Tiedemann, 255 f.n.

Paley, W., 341

Palingenesis (Haeckel), 258, 323

Pander, 113, 119-20, 133, 208, 209

Parallelism, Theory of. _See_ "Development, Meckel-Serres Law"
Three-fold. _See_ "Development, Meckel-Serres Law"

Paris Museum of Natural History, 19, 89, 101

Paul, 360

Pauly, A., 345

Perrault, C., 19

Perrier, E., 88, 359 f.n.

Pflueger, E., 317, 330

Philipeaux, 315

"Philosophy of Nature," 89, 94, 98, 203, 248

Phyletic Series, 359-61

Physiology, Separation from Morphology, 194, 247, 260, 314

Physiology of Development, 315

Planula Theory (Lankester), 295

Plato, 15

Pockels, 138

Poecilogeny (Giard), 347-8

Poli, 175

Polyphyletism--
Darwin, 238
Von Baer, 242, 356
Koelliker, Wigand, Naegeli, 356
Deperet, 360-1
Steinmann, 360 f.n.

Polyzoic Conception of Organism--
Duges, 87
Perrier, 88

Prevost and Dumas, 125 f.n., 134, 175, 186

Promorphology (Haeckel), 249

Protoplasm, 169, 188-9

Purkinje, 172, 173, 175, 176, 189

QUATREFAGES, A. de, 172, 195-6

RADL, E., on Goethe, 48
Correlation, 240 f.n., 241
On Darwin's Critics, 242 f.n.
On Cuvier's Critics, 278 f.n.

Rathke, H., 133, 136-7, 174, 194, 269, 351 f.n.
Discovery of Gill-slits in Pig and Chick, 134
Discovery of Gill-slits in Man, 135
Germ-Layer Theory, 136, 208
Embryological Criterion, 138, 140-1
Homologies of Gill-arches, 139-41, 146, 150
Development of Skull, 141, 150-4
Vertebral Theory of Skull, 141, 154-6
Embryological Archetype, 151, 153
Membrane and Cartilage Bones, 163, 166

Rauber, A., 330

Reaumur, 22, 315

Recapitulation Theory. _See_ "Development, Biogenetic Law"

Regeneration, 315, 318, 333, 346

Regulatory Processes in Development, 114, 319, 333, 346-7, 350

Rei