It is true that the opponents of evolution love to misrepresent the Monistic philosophy based on it as “Materialism,” and confuse the philosophic tendency of this name with a wholly unconnected and despicable moral materialism. Strictly speaking, it would be just as proper to call our system Spiritualism as Materialism. The real Materialistic philosophy affirms that the phenomena of life are, like all other phenomena, effects or products of matter. The opposite extreme, the Spiritualistic philosophy, says, on the contrary, that matter is a product of energy, and that all material forms are produced by free and independent forces. Thus, according to one-sided Materialism, the matter is antecedent to the living force; according to the equally one-sided view of the Spiritist, it is the reverse. Both views are Dualistic, and, in my opinion, both are false. For us the antithesis disappears in the Monistic philosophy, which knows neither matter without force nor force without matter. It is only necessary to reflect for some time over the question from the strictly scientific point of view to see that it is impossible to form a clear idea of either hypothesis. As Goethe said, “Matter can never exist or act without spirit, nor spirit without matter.”
The human “spirit” or “soul” is merely a force or form of energy, inseparably bound up with the material sub-stratum of the body. The thinking force of the mind is just as much connected with the structural elements of the brain as the motor force of the muscles with their structural elements. Our mental powers are functions of the brain as much as any other force is a function of a material body. We know of no matter that is devoid of force, and no forces that are not bound up with matter. When the forces enter into the phenomenon as movements we call them living or active forces; when they are in a state of rest or equilibrium we call them latent or potential. This applies equally to inorganic and organic bodies. The magnet that attracts iron filings, the powder that explodes, the steam that drives the locomotive, are living inorganics; they act by living force as much as the sensitive Mimosa does when it contracts its leaves at touch, or the venerable Amphioxus that buries itself in the sand of the sea, or man when he thinks. Only in the latter cases the combinations of the different forces that appear as “movement” in the phenomenon are much more intricate and difficult to analyse than in the former.
Our study has led us to the conclusion that in the whole evolution of man, in his embryology and in his phylogeny, there are no living forces at work other than those of the rest of organic and inorganic nature. All the forces that are operative in it could be reduced in the ultimate analysis to growth, the fundamental evolutionary function that brings about the forms of both the organic and the inorganic. But growth itself depends on the attraction and repulsion of homogeneous and heterogeneous particles. Seventy-five years ago Carl Ernst von Baer summed up the general result of his classic studies of animal development in the sentence: “The evolution of the individual is the history of the growth of individuality in every respect.” And if we go deeper to the root of this law of growth, we find that in the long run it can always be reduced to that attraction and repulsion of animated atoms which Empedocles called the “love and hatred” of the elements.
Thus the evolution of man is directed by the same “eternal, iron laws” as the development of any other body. These laws always lead us back to the same simple principles, the elementary principles of physics and chemistry. The various phenomena of nature only differ in the degree of complexity in which the different forces work together. Each single process of adaptation and heredity in the stem-history of our ancestors is in itself a very complex physiological phenomenon. Far more intricate are the processes of human embryology; in these are condensed and comprised thousands of the phylogenetic processes.
In my General Morphology, which appeared in 1866, I made the first attempt to apply the theory of evolution, as reformed by Darwin, to the whole province of biology, and especially to provide with its assistance a mechanical foundation for the science of organic forms. The intimate relations that exist between all parts of organic science, especially the direct causal nexus between the two sections of evolution—ontogeny and phylogeny—were explained in that work for the first time by transformism, and were interpreted philosophically in the light of the theory of descent. The anthropological part of the General Morphology (Book vii) contains the first attempt to determine the series of man’s ancestors (vol. ii, p. 428). However imperfect this attempt was, it provided a starting-point for further investigation. In the thirty-seven years that have since elapsed the biological horizon has been enormously widened; our empirical acquisitions in paleontology, comparative anatomy, and ontogeny have grown to an astonishing extent, thanks to the united efforts of a number of able workers and the employment of better methods. Many important biological questions that then appeared to be obscure enigmas seem to be entirely settled. Darwinism arose like the dawn of a new day of clear Monistic science after the dark night of mystic dogmatism, and we can say now, proudly and gladly, that there is daylight in our field of inquiry.
Philosophers and others, who are equally ignorant of the empirical sources of our evidence and the phylogenetic methods of utilising it, have even lately claimed that in the matter of constructing our genealogical tree nothing more has been done than the discovery of a “gallery of ancestors,” such as we find in the mansions of the nobility. This would be quite true if the genealogy given in the second part of this work were merely the juxtaposition of a series of animal forms, of which we gathered the genetic connection from their external physiognomic resemblances. As we have sufficiently proved already, it is for us a question of a totally different thing—of the morphological and historical proof of the phylogenetic connection of these ancestors on the basis of their identity in internal structure and embryonic development; and I think I have sufficiently shown in the first part of this work how far this is calculated to reveal to us their inner nature and its historical development. I see the essence of its significance precisely in the proof of historical connection. I am one of those scientists who believe in a real “natural history,” and who think as much of an historical knowledge of the past as of an exact investigation of the present. The incalculable value of the historical consciousness cannot be sufficiently emphasised at a time when historical research is ignored and neglected, and when an “exact” school, as dogmatic as it is narrow, would substitute for it physical experiments and mathematical formulæ. Historical knowledge cannot be replaced by any other branch of science.
It is clear that the prejudices that stand in the way of a general recognition of this “natural anthropogeny” are still very great; otherwise the long struggle of philosophic systems would have ended in favour of Monism. But we may confidently expect that a more general acquaintance with the genetic facts will gradually destroy these prejudices, and lead to the triumph of the natural conception of “man’s place in nature.” When we hear it said, in face of this expectation, that this would lead to retrogression in the intellectual and moral development of mankind, I cannot refrain from saying that, in my opinion, it will be just the reverse; that it will promote to an enormous extent the advance of the human mind. All progress in our knowledge of truth means an advance in the higher cultivation of the human intelligence; and all progress in its application to practical life implies a corresponding improvement of morality. The worst enemies of the human race—ignorance and superstition—can only be vanquished by truth and reason. In any case, I hope and desire to have convinced the reader of these chapters that the true scientific comprehension of the human frame can only be attained in the way that we recognise to be the sole sound and effective one in organic science generally—namely, the way of Evolution.
INDEX
A
Abiogenesis, [26]
Accipenser, [234]
Abortive ova, [55]
Achromatin, [42]
Achromin, [42]
Acœla, [221]
Acoustic nerve, the, [289,] [290]
Acquired characters, inheritance of, [349]
Acrania, the, [182]
Acroganglion, the, [268,] [275]
Adam’s apple, the, [184]
Adapida, [257]
Adaptation, [3,] [5,] [27]
After-birth, the, [167]
Agassiz, L., [34]
Age of life, [200]
Alimentary canal, evolution of the, [13,] [14,] [133,] [308–17]
— — structure of the, [169,] [308–10]
Allantoic circulation, the, [171]
Allantois, development of the, [166]
Allmann, [20]
Amblystoma, [243]
Amitotic cleavage, [40]
Ammoconida, [217]
Ammolynthus, [217]
Amnion, the, [115]
— formation of the, [134,] [244]
Amniotic fluid, the, [134]
Amœba, the, [47–9,] [210]
Amphibia, the, [239]
Amphichœrus, [221]
Amphigastrula, [80]
Amphioxus, the, [105,] [181–95]
— circulation of the, [184]
— cœlomation of the, [95]
— embryology of the, [191–95]
— structure of the, [183–88]
Amphirhina, [230]
Anamnia, the, [115]
Anatomy, comparative, [208]
Animalculists, [12]
Animal layer, the, [16]
Annelids, the, [142,] [219]
Annelid theory, the, [142]
Anomodontia, [246]
Ant, intelligence of the, [353]
Anthropithecus, [174,] [262]
Anthropogeny, [1]
Anthropoid apes, the, [166,] [173,] [262]
Anthropology, [1,] [35]
Anthropozoic period, [203]
Antimera, [107]
Anura, [243]
Anus, the, [317]
Anus, formation of the, [139]
Aorta, the, [327]
— development of the, [170]
Ape and man, [157,] [164,] [261,] [307,] [351]
Ape-man, the, [263]
Apes, the, [257–60]
Aphanocapsa, [210]
Aphanostomum, [221]
Appendicaria, [197]
Appendix vermiformis, the, [32]
Aquatic life, early prevalence of, [235]
Ararat, Mount, [24]
Archenteron, [64,] [74]
Archeolithic age, [203]
Archicaryon, [55]
Archicrania, [230]
Archigastrula, [65,] [193]
Archiprimas, [263]
Arctopitheca, [261]
Area, the germinative, [121]
Aristotle, [9]
Arm, structure of the, [306]
Arrow-worm, the, [191]
Arterial arches, the, [325–26]
— cone, the, [324]
Arteries, evolution of the, [170,] [323–24]
Articulates, the, [142,] [219]
— skeleton of the, [294]
Articulation, [141–42]
Aryo-Romanic languages, the, [203]
Ascidia, the, [181,] [188–90]
— embryology of the, [196–98]
Ascula, [217]
Asexual reproduction, [51]
Atlas, the, [247]
Atrium, the, [183,] [185]
— (heart), the, [326]
Auditory nerve, the, [289,] [290]
Auricles of the heart, [325]
Autolemures, [257]
Axolotl, the, [243]
B
Bacteria, [38,] [210]
Baer, K. E. von, [15–17]
Balanoglossus, [226]
Balfour, F., [21]
Batrachia, [241]
Bdellostoma Stouti, [78]
Bee, generation of the, [9]
Beyschlag, W., on evolution, [50]
Bilateral symmetry, [66]
— — origin of, [221]
Bimana, [258]
Biogenetic law, the, [2,] [21,] [23,] [179,] [349]
Biogeny, [2]
Bionomy, [33]
Bird, evolution of the, [245]
— ovum of the, [44–6,] [80–1]
Bischoff, W., [17]
Bladder, evolution of the, [244,] [339]
Blastæa, the, [206,] [213]
Blastocœl, the, [62,] [74]
Blastocrene, the, [99]
Blastocystis, the, [62,] [119,] [120]
Blastoderm, the, [62]
Blastodermic vesicle, the, [119]
Blastoporus, the, [64]
Blastosphere, the, [62,] [119]
Blastula, the, [62,] [74]
— the mammal, [119]
Blood, importance of the, [318]
— recent experiments in mixture of, [172]
— structure of the, [319]
Blood-cells, the, [319]
Blood-vessels, the, [318–25]
— development of the, [168]
— of the vertebrate, [110]
— origin of the, [320–21]
Boniface VIII, Bull of, [10]
Bonnet, [13]
Borneo nosed-ape, the, [164]
Boveri, Theodor, [185]
Brachytarsi, [257]
Brain and mind, [278,] [354–56]
— evolution of the, [8,] [275–80]
— in the fish, [276]
— in the lower animals, [275]
— structure of the, [273–74]
Branchial arches, evolution of the, [303]
— cavity, the, [183,] [189]
— system, the, [110]
Branchiotomes, [149]
Breasts, the, [113]
Bulbilla, [184]
C
Calamichthys, [234]
Calcolynthus, [217]
Capillaries, the, [323]
Caracoideum, the, [249]
Carboniferous strata, [202]
Carcharodon, [234]
Cardiac cavity, the, [170]
Cardiocœl, the, [328]
Caryobasis, [38,] [54]
Caryokinesis, [42]
Caryolymph, [38,] [54]
Caryolyses, [42]
Caryon, [37]
Caryoplasm, [37]
Catallacta, [213]
Catarrhinæ, the, [173,] [261]
Catastrophic theory, the, [24]
Caudate cells, [53]
Cell, life of the, [41–3]
— nature of the, [36–7]
— size of the, [38]
Cell theory, the, [18,] [36]
Cenogenesis, [4]
Cenogenetic structures, [4]
Cenozoic period, the, [203]
Central body, the, [38,] [42]
Central nervous system, the, [273]
Centrolecithal ova, [68]
Centrosoma, the, [38,] [42]
Ceratodus, the, [76,] [237]
Cerebellum, the, [274]
Cerebral vesicles, evolution of the, [276]
Cerebrum, the, [273]
Cestracion Japonicus, [75,] [79]
Chætognatha, [94]
Chick, importance of the, in embryology, [11,] [16]
Child, mind of the, [8,] [355]
Chimpanzee, the, [174,] [262]
Chiromys, [257]
Chiroptera, [258]
Chirotherium, [239]
Chondylarthra, [257]
Chorda, the, [17,] [95,] [107,] [183]
— evolution of the, [296]
Chordæa, the, [97]
Chordalemma, the, [296]
Chordaria, [97]
Chordula, the, [3,] [96,] [191]
Choriata, the, [166]
Chorion, the, [119]
— development of the, [165–6]
— frondosum, [255]
— læve, [255]
Choroid coat, the, [286]
Chorology, [33]
Chromacea, [209]
Chromatin, [42]
Chroococcacea, [210]
Chroococcus, the, [210]
Church, opposition of, to science in Middle Ages, [10]
Chyle, [318]
Chyle-vessels, [324]
Cicatricula, the, [45,] [81]
Ciliated cells, [53,] [193]
Cinghalese gynecomast, [114]
Circulation in the lancelet, [184]
Circulatory system, evolution of the, [321–25]
— — structure of the, [318]
Classification, [103]
— evolutionary value of, [33]
Clitoris, the, [345]
Cloaca, the, [249,] [317]
Cnidaria, [217]
Coccyx, the, [295]
Cochineal insect, the, [354]
Cochlea, the, [289]
Cœcilia, [241]
Cœcum, the, [310,] [317]
Cœlenterata, [20,] [91,] [93,] [104]
Cœlenteria, [221]
Cœloma, the, [21,] [64,] [91]
Cœlomæa, the, [98]
Cœlomaria, [21,] [91,] [104,] [221]
Cœlomation, [93–4]
Cœlom-theory, the, [21,] [93]
Cœlomula, the, [98]
Colon, the, [310,] [317]
Comparative anatomy, [31]
Conception, nature of, [51]
Conjunctiva, the, [286]
Conocyema, [215]
Convoluta, [221]
Copelata, the, [197]
Copulative organs, evolution of the, [344–45]
Corium, the, [108,] [268]
Cornea, the, [286]
Corpora cavernosa, the, [345,] [346]
Corpora quadrigemina, [274]
Corpora striata, [274]
Corpus callosum, the, [274]
Corpus vitreum, the, [285]
Corpuscles of the blood, [319]
Craniology, [303]
Craniota, the, [182,] [229]
Cranium, the, [299]
Creation, [23–4]
Cretaceous strata, [202]
Crossopterygii, [234]
Crustacea, the, [142,] [219]
Cryptocœla, [221]
Cryptorchism, [114]
Crystalline lens, the, [285]
— — development of the, [287]
Cutaneous glands, [268]
Cuttlefish, embryology of the, [9]
Cuvier, G., [17,] [24]
Cyanophycea, [209]
Cyclostoma, the, [188,] [230–32]
— ova of the, [75]
Cyemaria, [214]
Cynopitheca, [262]
Cynthia, [191,] [196]
Cytoblastus, the, [37]
Cytodes, [40]
Cytoplasm, [37,] [38]
Cytosoma, [37]
Cytula, the, [54]
D
Dalton, [15]
Darwin, C., [2,] [5,] [23,] [28–9]
Darwin, E., [28]
Darwinism, [5,] [28]
Decidua, the, [167]
Deciduata, [255]
Deduction, nature of, [208]
Degeneration theory, the, [219]
Dentition of the ape and man, [259]
Depula, [62]
Descent of Man, [30]
Design in organisms, [33]
Deutoplasm, [44]
Devonian strata, [202]
Diaphragm, the, [309]
— evolution of the, [328]
Dicyema, [215]
Dicyemida, [215]
Didelphia, [248]
Digonopora, [223]
Dinosauria, [202]
Dipneumones, [238]
Dipneusta, [235–38]
— ova of the, [75]
Dipnoa, [236]
Directive bodies, [54]
Discoblastic ova, [68]
Discoplacenta, [255]
Dissatyrus, [174]
Dissection, medieval decrees against, [10]
Dohrn, Anton, [219]
Döllinger, [15]
Dorsal furrow, the, [125]
— shield, the, [123]
— zone, the, [129]
Dromatherium, [248]
Dualism, [6]
Dubois, Eugen, [263]
Ductus Botalli, the, [350]
Ductus venosus Arantii, [350]
Duodenum, the, [309,] [317]
Duration of embryonic development, [199]
— of man’s history, [199]
Dysteleology, [32]
— proofs of, [349]
E
Ear, evolution of the, [288–92]
— structure of the, [288]
— uselessness of the external, [32]
Ear-bones, the, [289]
Earth, age of the, [200–201]
Echidna hystrix, [249]
Ectoblast, [20,] [64]
Ectoderm, the, [20,] [64]
Edentata, [250]
Efficient causes, [6]
Egg of the bird, [44–6,] [81]
— or the chick, priority of the, [211]
Elasmobranchs, the, [79]
Embryo, human, development of the, [158]
Embryology, [2]
— evolutionary value of, [34]
Embryonic development, duration of, [199]
— disk, the, [121–22]
— spot, the, [125]
Encephalon, the, [273]
Endoblast, [20,] [64]
Endothelia, [321]
Enterocœla, [93,] [223]
Enteropneusta, [226]
Entoderm, the, [20,] [64]
Eocene strata, [203]
Eopitheca, [259]
Epiblast, [20,] [64]
Epidermis, the, [108,] [268]
Epididymis, the, [342]
Epigastrula, [80]
Epigenesis, [11,] [13]
Epiglottis, the, [309]
Epiphysis, the, [108]
Episoma, [129]
Episomites, [130,] [194]
Epispadia, [346]
Epithelia, [37]
Epitheria, [243,] [253]
Epovarium, the, [342]
Equilibrium, sense of, [291]
Esthonychida, [257]
Eustachian tube, the, [289]
Eutheria, [253]
Eve, [12]
Evolution theory, the, [11,] [208]
— inductive nature of, [30]
Eye, evolution of the, [285–88]
— structure of the, [285]
Eyelid, the third, [32]
Eyelids, evolution of the, [288]
F
Fabricius ab Aquapendente, [10]
Face, embryonic development of the, [284]
Fat glands in the skin, [269]
Feathers, evolution of, [270]
Fertilisation, [51]
— place of, [119]
Fin, evolution of the, [239,] [304]
Final causes, [6]
Flagellate cells, [193]
Floating bladder, the, [233,] [241]
— — evolution of the, [314]
Fœtal circulation, [170–71]
Food-yelk, the, [67,]
Foot, evolution of the, [241,] [304–6]
— of the ape and man, [258–59]
Fore brain, the, [278]
Fore kidneys, the, [336,] [337]
Fossiliferous strata, list of, [201]
Fossils, [180]
— scarcity of, [208]
Free will, [356]
Friedenthal, experiments of, [172]
Frog, the, [241–42]
— ova of the, [71–2]
Frontonia, [224]
Function and structure, [7]
Furcation of ova, [72]
G
Gaertner’s duct, [341,] [350]
Ganglia, commencement of, [268]
Ganglionic cell, the, [39]
Ganoids, [233,] [234]
Gastræa, the,
[3,] [20,] [206]
— formation of the, [213]
Gastræa theory, the, [20,] [64,] [69]
Gastræads, [69,] [214]
Gastremaria, [214]
Gastrocystis, the, [62,] [119,] [120]
Gastrophysema, [215]
Gastrotricha, [224]
Gastrula, the, [3,] [20,] [62]
Gastrulation, [62]
Gegenbaur, Carl, [220]
— on evolution, [32]
— on the skull, [300–1]
Gemmation, [331]
General Morphology, [8,] [29]
Genesis, [23]
Genital pore, the, [335]
Geological evolution, length of, [200]
— periods, [201]
Geology, methods of, [180]
— rise of, [24]
Germ-plasm, theory of, [349]
Germinal disk, [46,] [81]
— layers, the, [14,] [16]
— — scheme of the, [92]
— spot, the, [44]
— vesicle, the, [43,] [54]
Germinative area, the, [121]
Giant gorilla, the, [176]
Gibbon, the, [173,] [262]
Gill-clefts and arches, [110]
— formation of the, [151–52,] [303]
Gill-crate, the, [183,] [189]
Gills, disappearance of the, [244]
Glœocapsa, [210]
Gnathostoma, [230,] [232]
Goethe as an evolutionist, [27,] [299]
Goitre, [110]
Gonads, the, [111]
— formation of the, [149–50]
Gonidia, [334]
Gonochorism, beginning of, [322]
Gonoducts, [335]
Gonotomes, [146,] [149]
Goodsir, [189]
Gorilla, the, [174,] [176,] [262]
Graafian follicles, the, [17,] [119,] [347]
Gregarinæ, [211]
Gullet-ganglion, the, [190]
Gut, evolution of the, [310–17]
Gyrini, [242]
Gynecomastism, [114]
H
Hag-fish, the, [188]
Hair, evolution of the, [270]
— on the human embryo and infant, [271]
Hair, restriction of, by sexual selection, [271]
Haliphysema, [215]
Halisauria, [202]
Haller, Albrecht, [12]
Halosphæra viridis, [213]
Hand, evolution of the, [250,] [304–6]
— of the ape and man, [258]
Hapalidæ, [261]
Harderian gland, the, [288]
Hare-lip, [284]
Harrison, Granville, [161]
Hartmann, [262]
Harvey, [10]
Hatschek, [192]
Hatteria, [243,] [246]
Head-cavity, the, [138]
Head-plates, the, [149]
Heart, development of the, [7,] [10,] [111,] [151,] [170,] [322,] [324–27]
— of the ascidia, [190]
— position of the, [327]
Helmholtz, [207]
Helminthes, [223]
Hepatic gut, the, [109,] [316]
Heredity, nature of, [3,] [5,] [27,] [56–7,] [349]
Hermaphrodism, [9,] [23,] [114,] [218,] [322,] [346]
Hertwig, [21]
Hesperopitheca, [259]
His, W., [19]
Histogeny, [18,] [19]
History of Creation, [6,] [30]
Holoblastic ova, [67,] [71,] [77]
Homœosaurus, [244,] [246]
Homology of the germinal layers, [20]
Hoof, evolution of the, [270]
Hunterian ligament, the, [344]
Huxleian law, the, [171,] [257,] [262]
Huxley, T. H., [7,] [20,] [29]
Hydra, the, [69,] [217]
Hydrostatic apparatus in the fish, [315]
Hylobates, [173,] [262]
Hylodes Martinicensis, [241]
Hyoid bone, the, [299]
Hypermastism, [113]
Hyperthelism, [113]
Hypoblast, [20,] [64]
Hypobranchial groove, the, [110,] [184,] [226,] [316]
Hypodermis, the, [268]
Hypopsodina, [257]
Hyposoma, the, [129]
Hyposomites, [130,] [194]
Hypospadia, [346]
I
Ichthydina, [224]
Ichthyophis glutinosa, [80]
Ictopsida, [257]
Ileum, the, [310]
Immortality, Aristotle on, [10]
Immortality of the soul, [58]
Impregnation-rise, the, [55]
Indecidua, [255]
Indo-Germanic languages, [203]
Induction and deduction, [31,] [208]
Inheritance of acquired characters, [349]
Insects, intelligence of, [353]
Interamniotic cavity, the, [165]
Intestines, the, [309,] [316–17]
Invagination, [62]
Iris, the, [286]
J
Jacchus, [261]
Java, ape-man of, [263,] [264]
Jaws, evolution of the, [301]
Jurassic strata, [202]
K
Kant, dualism of, [25]
Kelvin, Lord, on the origin of life, [207]
Kidneys, the, [111]
— formation of the, [150–51,] [336–42]
Klaatsch, [262]
Kölliker, [21]
Kowalevsky, [191]
L
Labia, the, [346]
Labyrinth, the, [290]
Lachrymal glands, [269]
Lamarck, J., [23,] [25–7]
— theories of, [26,] [349]
Lamprey, the, [230]
— ova of the, [75]
Lancelet, the, [60,] [181–95]
— description of the, [105]
Languages, evolution of, [203]
Lanugo of the embryo, [271]
Larynx, the, [309]
— evolution of the, [314]
Latebra, the, [45]
Lateral plates, the, [129]
Laurentian strata, [201]
Lecithoma, the, [117]
Leg, evolution of the, [304]
— structure of the, [306]
Lemuravida, [257]
Lemurogona, [257]
Lemurs, the, [257]
Lepidosiren, [257]
Leucocytes, [319]
Life, age of, [200]
Limbs, evolution of the, [152,] [239,] [304]
Limiting furrow, the, [133]
Linin, [42]
Liver, the, [309,] [317]
Long-nosed ape, the, [164]
Love, importance of in nature, [332]
Lungs, the, [110]
— evolution of the, [241,] [314–15]
Lyell, Sir C., [24]
Lymphatic vessels, the, [318]
Lymph-cells, the, [319]
M
Macrogonidion, [331]
Macrospores, [331]
Magosphæra planula, [213]
Male womb, the, [344,] [350]
Mallochorion, the, [166]
Mallotheria, [257]
Malpighian capsules, [339,] [341]
Mammal, characters of the, [112]
— gastrulation of the, [84]
Mammals, unity of the, [247–48]
Mammary glands, the, [113,] [269]
Man and the ape, relation of, [262,] [351]
— origin of, [29]
Man’s Place in Nature, [7,] [29,] [351]
Mantle, the, [189]
Mantle-folds, the, [185]
Marsupials, the, [250–52]
— ova of the, [85]
Materialism, [356]
Mathematical method, the, [30]
Mechanical causes, [6]
— embryology, [8,] [19,] [22]
Meckel’s cartilage, [304]
Medulla capitis, the, [273]
— oblongata, the, [274]
— spinalis, the, [273]
Medullary groove, the, [125]
— tube, the, [107,] [128]
— — formation of the, [131,] [133,] [227,] [267,] [276]
Mehnert, E., on the biogenetic law, [5]
Meroblastic ova, [67,] [71,] [78]
Merocytes, [68,] [321]
Mesentery, the, [98,] [109,] [310,] [316]
Mesocardium, the, [327]
Mesoderm, the, [20,] [64,] [90,] [93]
Mesogastria, [215]
Mesonephridia, the, [338]
Mesonephros, the, [336]
Mesorchium, the, [344]
Mesovarium, the, [344]
Mesozoic period, the, [202]
Metogaster, the, [64]
Metagastrula, the, [67]
Metamerism, [142]
Metanephridia, the, [341]
Metanephros, the, [336]
Metaplasm, [39]
Metastoma, [64,] [222]
Metatheria, [248]
Metazoa, [20,] [62]
Metovum, the, [81]
Microgonidian, [331]
Microspores, [331]
Middle ear, the, [291]
Migration, effect of, [33]
Milk, secretion of the, [269]
Mind, evolution of, [353–54]
— in the lower animals, [353]
Miocene strata, [203]
Mitosis, [40,] [41]
Monera, [40,] [206,] [209]
Monism, [6,] [356]
Monodelphia, [248]
Monogonopora, [223]
Monopneumones, [238]
Monotremes, [118,] [249]
— ova of the, [84]
Monoxenia Darwinii, [60]
Morea, the, [212]
Morphology, [2,] [27]
Morula, the, [62,] [212]
Motor-germinative layer, the, [19]
Mouth, development of the, [124,] [139]
— structure of the, [308]
Mucous layer, the, [16]
Müllerian duct, the, [341]
Muscle-layer, the, [16]
Muscles, evolution of the, [307]
— of the ear, rudimentary, [292]
Myotomes, [108,] [146]
Myxinoides, the, [188,] [230]
N
Nails, evolution of the, [270]
Nasal pits, [284]
Natural philosophy, [25]
— selection, [26,] [28,] [349]
Navel, the, [117,] [134]
Necrolemurs, [257]
Nectocystis, the, [314]
Nemertina, [224–26]
Nephroduct, evolution of the, [338–39]
Nephrotomes, [149,] [338]
Nerve-cell, the, [39]
Nerves, animals without, [267]
Nervous system, evolution of the, [7,] [267]
Neurenteric canal, the, [127]
Nictitating membrane, the, [32,] [286,] [288]
Nose, the, in man and the ape, [164]
— development of the, [282–85]
— structure of the, [283]
Notochorda, the, [107]
Nuclein, [37]
Nucleolinus, [44]
Nucleolus, the, [38,] [44,] [54]
Nucleus of the cell, [37]
O
Œsophagus, the, [309,] [316]
Oken, [5,] [27,] [300]
Oken’s bodies, [339]
Oligocene strata, [203]
Olynthus, [217]
On the generation of animals, [9]
Ontogeny, [2,] [23]
— defective evidence of, [208]
Opaque area, the, [122]
Opossum, the, [252]
— ova of the, [85]
Optic nerve, the, [287]
Optic thalami, [274]
— vesicles, [286]
Orang, the, [174,] [262]
Ornithodelphia, [248]
Ornithorhyncus, [85,] [249]
Ornithostoma, [249]
Ossicles of the ear, [289]
Otoliths, [289]
Ova, number of, [347]
— of the lancelet, [192]
Ovaries, evolution of the, [333–34]
Oviduct, origin of the, [335,] [342]
Ovolemma, the, [44]
Ovulists, [12]
Ovum, discovery of the, [16]
— nature of the, [40
— size of the, ][44]
P
Pachylemurs, the, [257]
Pacinian corpuscles, [282]
Paleontology, [2]
— evolutionary evidence of, [31]
— incompleteness of, [208]
— rise of, [24]
Paleozoic age, the, [202]
Palingenesis, [4]
Palingenetic structures, [4]
Palæhatteria, [244,] [246]
Panniculus carnosus, the, [350]
Paradidymis, the, [342]
Parietal zone, the, [129]
Parthenogenesis, [9,] [13]
Pastrana, Miss Julia, [164]
Pedimana, [252]
Pellucid area, the, [122]
Pelvic cavity, the, [138]
Pemmatodiscus gastrulaceus, [215]
Penis-bone, the, [346]
Penis, varieties of the, [345]
Peramelida, [254]
Periblastic ova, [68]
Peribranchial cavity, the, [185,] [190]
Pericardial cavity, the, [328]
Perichorda, the, [108,] [183]
— formation of the, [136]
Perigastrula, [89]
Permian strata, [202]
Petromyzontes, the, [188,] [230]
Phagocytes, [49,] [320]
Pharyngeal ganglion, the, [275]
Pharynx, the, [309]
Philology, comparison with, [203]
Philosophie Zoologique, [25]
Philosophy and evolution, [6]
Phycochromacea, [209]
Phylogeny, [2,] [23]
Physemaria, [214]
Physiology, backwardness of, [7]
Phytomonera, [209]
Pineal eye, the, [108]
Pinna, the, [291]
Pithecanthropus, [263,] [264]
Pithecometra-principle, the, [171]
Placenta, the, [166,] [253–54]
Placentals, the, [166]
— characters of the, [253]
— gastrulation of the, [86]
Planocytes, [49,] [320]
Plant-louse, parthenogenesis of the, [13]
Planula, the, [89]
Plasma-products, [38,] [39]
Plasson, [40,] [59]
Plastids, [36,] [40,] [209]
Plastidules, [59]
Platodaria, [221]
Platodes, the, [221]
Platyrrhinæ, [261]
Pleuracanthida, [234]
Pleural ducts, [328]
Pliocene strata, [203]
Polar cells, [54]
Polyspermism, [58]
Preformation theory, the, [11]
Primary period, the, [202]
Primates, the, [157,] [257–60]
Primatoid, [263]
Primitive groove, the, [69,] [82,] [124,] [125]
— gut, the, [20,] [63,] [214]
— kidneys, the, [111,] [337]
— mouth, the, [20,] [63]