Hence in our phylogenetic inquiry and in the comparative study of the living, divergent descendants, there can only be a question of determining the greater or less remoteness of the latter from the ancestral form.
In explaining thephylogenetic origin of the gastraea in the light of this ontogenetic process, we may assume that the one-layered cell-community of the blastaea began to take in food more largely at one particular part of its surface.
As the human embryo passes through the gastrula-form like that of all the other Metazoa, we can trace itsphylogenetic origin to the Gastraea.
We must try to piece together a fairly complete picture of the series of our ancestors from the various phylogenetic fragments that we find in the different groups of the animal kingdom.
The ontogenetic facts that we gather from this sole survivor of the Acrania are the more valuable for phylogenetic purposes, as paleontology, unfortunately, throws no light whatever on the origin of the Vertebrates.
We shall have the same experience in the study of the organs in detail, and I shall be compelled to give simultaneously their ontogenetic and phylogenetic origin.
It is a universal and natural procedure in phylogenetic development that the stem-forms themselves, with their specific peculiarities, have been extinct for some time.
But the vast empirical material that it has accumulated in its extensive literature is mere dead and sterile erudition until it is vivified and illumined by phylogenetic speculation.
In these it has only a phylogenetic interest as a rudimentary organ, with no actual physiological significance.
Within the vertebrate stem there is, as we have already seen, so complete an agreement in structure and embryology that it is impossible to doubt their phylogenetic unity.
We must have knowledge to conceive ourselves as products of a phylogenetic history, and thus cannot deduce from it the fact, and, still less, the justification of knowledge.
If we have in mind the inner nature of the organism, there is, properly speaking, no such specific phenomenon as heredity, since the phylogenetic line is a continuous idioplasmic individual.
Since the simplest plants are cells and the more complex ones are formed from cells, a whole phylogenetic line may be regarded as a series of cell generations following one after another.
By the further phylogenetic process of reduction the intermediate forms are suppressed.
Along with the above named phylogenetic processes, which take place by the automatic increase of the idioplasm, external influences are always active.
By virtue of the automatic variation of the idioplasm the ontogenies of a phylogenetic line attain to a continually more complex organization and greater differentiation of function.
The continued phylogenetic formation of the threads of idioplasm takes place by growth in the cross section, which contains the sum of all the determinants and changes in general only when new rows of micellae are intercalated.
He aptly says, that natural selection prunes the phylogenetic tree, but does not cause new branches to grow.
The above described phylogenetic perfecting process of the idoplasm, which operates through internal causes, is scarcely affected by differences of nutrition and by climatic conditions influencing nutrition.
From the fact that a phylogenetic race is thrown repeatedly among different external conditions, it may at last unite in its idioplasm a large number of developing, mature, and vanishing adaptation determinants.
Their ontogenetic history does not explain their true significance; this can be known only in a phylogenetic way by comparison of one phenomenon with those phenomena from which it has arisen in the course of evolution.
There is manifested in this phylogenetic process the tendency of the plant to combine in the higher stages into one complex whole those parts which in the lower stages tend to be independent.
The idea of ontogenetic degeneration is intimately bound up with the idea of phylogenetic degeneration.
It may be the ancestral form of it (both in an ontogenetic and phylogenetic sense).
May be considered in a phylogenetic and ontogenetic sense as a further developmental stage of Desmocampe aphrodite and Ommatocampe nereis, Pl.
The eight genera of Pylodiscida represent therefore a continuous phylogenetic series.
Also in many cases the phylogenetic relations of the different #Sphaeroidea# are more complicated than would appear from both these classificatory principles.
The important question as to the phylogenetic origin of Archidiscus can be answered in a twofold way.
The morphological references and the phylogenetic affinities of all #Prunoidea# are so complex, that they seem to represent a quite natural group; all forms of it may be derived from the common ancestral form Cenellipsis.
The fact that there are many Radiolaria living at the present day, whose shells are found fossil in Tertiary rocks, is of great phylogenetic and geological significance.
From a phylogenetic point of view, the conclusion is allowable that the precocious forms are secondary, and have arisen by adaptive modification from the primitive serotinous stem.
The phylogenetic relationship of these families of #Larcoidea# is probably very complicated and demands closer investigation (compare pp.
These interesting morphological facts are capable of direct phylogenetic application, and furnish valuable proofs of the truth of the theory of descent.
This remarkable ontogenetic metamorphosis also can be fully explained by a corresponding phylogenetic process, and affords a very fine instance of the inheritance of acquired characters.
It is especially notable that evolution is presented in it as the one possible and natural theory of the origin of species; even morphology and classification are treated explicitly as "phylogenetic sciences.
In the latter book I also worked out the important conclusions that follow from this monistic reform of the theory of germinal layers for the phylogenetic natural classification of the animal kingdom.
The error of this dualistic notion is clear the moment one impartially considers the whole gradation of forms of reproduction, from the simplest cell-division to the most elaborate form of sexual generation, inphylogenetic connection.
They are phylogenetic outcomes of the manifold differentiations which the originally homogeneous and structureless plasm has undergone in the course of many millions of years.
Wigand assumed for the origin of each species a special primitive cell and a long phylogenetic development of this; Reinke prefers a stem, composed of a number of species.
Riddle how important a part of our monistic philosophy this phylogenetic anthropology is.
They are determined by the complicated structure of the psychoplasm, which has been gradually acquired by phylogenetic processes in the course of millions of years.
On the strength of the ontogenetic facts, which fall under direct observation, we infer that there was a corresponding development in the phylogenetic series of our animal ancestors.
Comparative anatomy affords a number of most valuable arguments for otherphylogenetic questions as well as progressive heredity; and the same may be said of comparative anatomy and comparative ontogeny.
My chief aim was, on the one hand, to construct a natural system of organisms on the basis of their ancestral history, and on the other hand to prove the mechanical character of the phylogenetic process.
It remains to be considered to what extent the several natural groups of plants classed together in the Bryophyta can be placed in a phylogenetic relation to one another.
The Ontogenetic Against the Phylogenetic Elements in the Psychoses of the Colored Race.
Phylogenetic Elements in the Psychoses of the Negro.
It is evident that these facts also point to the skate's organ being in course of phylogenetic evolution.
The answer is found in the fact that this is the order of change in the phylogenetic series.
Coming now to bones, we have a singularly complete record of transition from one type or pattern of structure to another in the phylogenetichistory of tails.
The first may conveniently be the phylogenetic interpretation of the contrast between "membrane" and "cartilage" bones.
It was studied as a fact of embryology and withoutphylogenetic bias by men like Oppel, Keibel, Mehnert, O.
It is thus in the long run functioning that brings aboutphylogenetic progression, absence of functional activity that causes phylogenetic regression.
Upon the Gastræa theory Haeckel based a system of phylogenetic classification which was intended to replace Cuvier's and von Baer's doctrine of Types.
This is typical of Haeckel's phylogenetic speculations.
His considered judgment as to the phylogenetic value of the biogenetic law closely resembles that formed by von Baer, for he admits recapitulation only as regards the single organs, not as regards the organism as a whole.
In his construction of phylogenetic trees he was so confident in the truth of his biogenetic law that he largely disregarded and consistently minimised the importance of the evidence from palæontology.
Knowledge of the life histories of the other species of Phyllomedusa should aid in the interpretation of the phylogeneticrelationships of the several groups of frogs now assigned to that genus.
The vast treasures of theory and example which he had accumulated were given to the world, the notion of special creations was exploded, and the facts of phylogenetic evolution won general acceptance.
The best athletic sports and games a composed of these racially old elements, so that phylogenetic muscular history is of great importance.
The gradual acquirement of the erect position by the human infant admirably repeats this long phylogenetic evolution.
It will be noted that the phylogenetic order follows that of Grinnell rather than the one proposed herein.
If these specimens referred to by Wood and Wilson are true heteromyids then a change in the phylogenetic scheme proposed by Wood (1935) would be necessary.
It is true that my hypotheses were in many cases supplemented and corrected in detail by later phylogenetic research; yet I am convinced that the ancestral tree of human origin which I have sketched therein is substantially correct.
August Schleicher, of Jena, in particular, has proved that the historical development of language takes place under the same phylogenetic laws as the evolution of other physiological faculties and their organs.
This great task of separating the different steps in the psychological ladder, and proving their unbroken phylogenetic connection, has only been seriously attempted during the last ten years, especially in the splendid work of Romanes.
This fundamental hypothesis of rational phylogeny is based, in virtue of the phylogenetic law, on the familiar embryological fact that every man, like every other metazoon (i.
We must admit that we are here, as we are in every branch of phylogenetic research, driven to the construction of a number of hypotheses in order to fill up the considerable lacunae of empirical phylogeny.
In my latest attempt[9] to arrange the advanced system of placentals in phylogenetic order I have substituted eight of these legions for the twenty-six orders, and shown that these may be reduced to four main groups.
The great phylogenetic significance of the resemblance we have described is seen, not only in the comparison of the embryos of vertebrates, but also in the comparison of their protective membranes.
If so, the species fall into a reasonablephylogenetic scheme that has microcephala as the extant species most like the ancestral stock.
The whole genus calls for careful and protracted study; and the present so-called species are like something new on the world; as full of vagaries as though but just entered upon their phylogenetic race.
Nevertheless, much has already been learned concerning the mutual relations of the carnivorous families, and several phylogenetic series, notably that of the dogs, are quite complete.
By the aid of the correlated ontogenetic stages and the succession of the adult forms in the rocks, many phylogenetic series have been established and a basis for the natural arrangement of the whole class has been laid.
It is difficult to believe that all those likenesses should have been independently acquired and are without phylogenetic significance.
Very beautiful phylogenetic series have already been established among these most interesting and marvellously preserved fossils, but lack of space forbids a consideration of them.
The long extinct class of crustacea known as the Trilobites are likewise very favourable subjects for phylogenetic studies.
Every sexual differentiation in organisms, which occurred in the course of phylogenetic development, was followed by fertilisation and therefore by the creation of a diploid or double-chromosome product.
But phylogenetic monogamy is by no means identical with the religious or other formality of our present legal monogamy.
Among the polyandrous people of Thibet jealousy appears to be completely absent: this may be the result of custom or may be due to phylogenetic instinct.
I have thus endeavored to acquaint the reader with the two sources of our sexual sensations and sentiments--the hereditary or phylogenetic source, and the source acquired and adapted by the individual.
But those who believe that negroes are capable of acquiring a higher civilization without undergoing a phylogenetic cerebral transformation for a hundred thousand years, are Utopians.
Moreover, it presents an individual or ontogenetic evolution during the life of each person, which in its principal traits is predetermined in the germ, by the phylogenetic or hereditary energies of the species.
As the result of the evolution of these two phylogenetic systems of motor phenomena tending to establish conjugation, we obtain for each sex two categories of sexual formations: (1).
Extension of communication on the surface of the earth causes the artificial development of social organization to advance much more rapidly than the natural phylogenetic development by evolution of the sentiments or social instincts.
This is simply a question of natural phylogenetic adaptation.
This denture is nothing else than a phylogenetic incident in the ontogeny of the whale.
But a social organization can never violate with impunity the true laws of human nature which are deeply rooted in our phylogenetic instincts, without disastrous effects.
The origin of law is in moral conscience, a phylogenetic derivative of the sentiments of sympathy, i.
This fidelity has therefore deep phylogenetic roots in our nature, and we shall see later on that we cannot neglect it without compromising our social state (Chap.
From the phylogenetic point of view we can only compare ourselves to the higher apes, by their analogies with primitive man.
The case where germinal material is influenced by causes which do effect a re-shuffling of its “molecules,” so that a permanent phylogenetic change does result.
The larval metamorphoses of the Crustacea have attracted much attention, and have been the subject of much discussion in view of their bearing on the phylogenetic history of the group.
The new impulse given to biological research by the publication of the Origin of Species bore fruit in Fritz Muller's Fur Darwin, in which an attempt was made to reconstruct the phylogenetic history of the class.
Although fossil remains of Crustacea are abundant, from the most ancient fossiliferous rocks down to the most recent, their study has hitherto contributed little to a precise knowledge of the phylogenetic history of the class.
On this view, the nauplius, while no longer regarded as reproducing an ancestral type, does not altogether lose its phylogenetic significance.
This chelate condition may be assumed by almost any of the appendages, and sometimes it appears in different appendages in closely related forms, so that no very great phylogenetic importance can in most cases be attached to it.
Tentative arrangement of species of the genus Geomys, depicting phylogenetic trends and probable relationships within the genus.
It is of importance to know that according to palaeontological investigation, empiric systematizing and phylogenetic classification do not always coincide, as, for instance, in the case of the ammonites.
The phylogenetic school commits the capital mistake of presenting a transformation which can be realized only in logical concepts, as an actually occurring process, and of confounding an abstract operation with concrete fact.
