The homologiesindicated are, however, by no means established.
The physiological significance, and the homologies of many parts are as yet altogether obscure.
Loven has taken, judging from a single sentence, the same view of the homologies of the external parts as I have done; in his description of Alepas squalicola, (Ofversigt of Kongl.
I enter on the subject of the metamorphoses the more readily, as by this means alone can the homologies of the different parts be clearly understood.
I feel much confidence, that the homologies here given are correct.
In one family there are well-developed branchiae, which differ entirely in their homologies and position from these organs in all other Crustaceans.
On the Homologiesof the Carapace and Shelly Valves.
This question and the whole subject of the homologies of the several parts of a Cirripede, will be discussed under the head of the Metamorphoses of the Balanidae.
Before proceeding to make a few additional remarks and corrections to my former description of the pupa, it will be advisable, on account of the importance of the subject, to discuss the homologies of the limbs.
A discussion on the homologies of the different parts is given under the head of the Metamorphoses of the Balanidae.
For the true homologies of the sclerodermic plates, or Shelly valves, with which the external covering of Cirripedes is so generally strengthened, we must, I believe, look to the carapace of the Podophthalmia.
This is very distinct in the canine teeth of the Carnivora, and is a useful guide in determining the homologies of the teeth of the two jaws.
Sladen, "Homologies of the Primary Larval Plates in the Test of Brachiate Echinoderms," Quart.
But, however correct the observations and the homologies of MacBride may be, they do not, as Bury (op.
But the study that should elucidate the fundamental similarities orhomologies between the several classes, and should suggest the relations of the Echinoderma to other phyla, had scarcely begun.
Now, one of the strongest proofs of the truth of evolution is taken from the homologies of animal structure.
From homologies I should look at it as certain that all mammals had descended from some single progenitor.
You will see in your mind the kind of arguments which made me think it probable, and no one fact had so great an effect on me as your most curious remarks on the apparent homologies of the head of Vertebrata and Articulata.
He thus determined the homologies on the female side.
In tracing the homologies of the same part in different members of a class, nothing is more common, or more necessary, than the use and discovery of rudiments.
Mode of origin andhomologies of the germinal layers, pp.
If Goette's facts are to be trusted, and they have been to a large extent confirmed by Hoffmann, his homologies appear to be satisfactorily established.
In these lectures Huxley disproved the then widely accepted view that the skull was composed of four vertebrae; and laid the foundation of a more satisfactory method of dealing with the homologies of its constituent parts.
The exact origin of the cartilaginous tube just described is a question of fundamental importance with reference to the origin of the vertebral column and the homologies of its constituent parts; but is by no means easy to settle.
The former may be spoken of as the brain, and the latter as the spinal cord; although the homologies of these two parts are quite uncertain.
The homologies of the episternum are much disputed.
In Ganoidei and Teleostei there is very great difficulty in determining the homologiesof the ribs.
The interclavicle (episternum) is held by Goette to be developed from a paired formation at the free ventral ends of the clavicles, but he holds views which are in many respects original as to its homologies in Mammalia and Amphibia.
Defn: Homogenous; -- applied to that class of homologies which arise from similarity of structure, and which are taken as evidences of common ancestry.
Defn: To determine the homologies or structural relations of.
They too had recognised homologies of organs; they too had interpreted rudimentary organs as vestiges of an original plan.
In determininghomologies Owen remained true to Geoffroy's principle of connections.
And the surest way to determine the true homologies of parts will be to study their early development.
Most of the ordinary homologies of structure in air-breathing Vertebrates have already been seized, he continues, for they are more or less obvious, and many intermediate states exist (p.
In a third paper of about the same time he tried to establish the homologies of the segments throughout the Articulate series--with less success than Savigny.
Vertebrates, with the homologies of the bones of the sternum, and with the determination of the pieces of the skull, particularly in the crocodile.
The recognition of serial homologies constituted a real advance in morphology; the "philosophical" idea of the repetition of the whole in the parts led to many absurdities.
Blood-relationship becomes dubious exactly in proportion as the proof of homologies is uncertain" (Elements, p.
Much difference of opinion reigned as to the true homologies of the brain and mouth of Annelids and Vertebrates.
Further, he does not always remain true to his principles, for he does not establish homologies of parts entirely by their connections but sometimes by their functions as well.
His main theoretical views are to be found in his volume On the Archetype and Homologies of the Vertebrate Skeleton (London, 1848).
But these homologies are still determined solely by the relative positions and connections of the parts, just as homologies are determined in the last of all the stages of development, the adult state.
But some of his homologies showed morphological insight, e.
Homologies were considered more interesting than analogies, vestigial organs more interesting than foetal and larval adaptations.
Further study, however, of thehomologies of these peculiar appendages, and especially a knowledge of the embryological development of Lepisma and Machilis, is needed before this interesting point can be definitely settled.
These homologies have never been made before, so far as the writer is aware, but they seem natural, and suggested by a careful examination and comparison with the above-mentioned mandibulate insects.
And no investigator of homologiesdoubts that a considerable number of the bones which form the skull of any osseous fish are distinctly homologous with the cranial bones of man.
And if such a power can be shown to be necessary in this instance, it may also be legitimately used to explain such serialhomologies as those of the centipede's segments and of the joints of the backbone.
He would explain the serial homologies of such creatures as the lobster and centipede thus: Animals of a very low grade propagate themselves by spontaneous fission.
But there are, it is here contended, abundant reasons for thinking that the predominant agent in the production of the homologies of the limbs is an internal force or tendency.
The brain of the hagfish differs widely from that of the higher fishes, and the homologies of the different parts are still uncertain.
There may be doubt even of the homologies of the gill-slits themselves.
Homologies of parts are best determinable, ceteris paribus, in the most nearly related forms.
This would evade the great difficulties which have beset those who have endeavored to establish the homologies of the elements of the pentadactyle limb with those of any type of fully formed fin.
Without considering Polypterus, it is not possible to interpret the homologies of the cranium of the amphibians and the sharks.
Gill has made an elaborate attempt to work out the homologies of the bones of the pectoral limb.
All thesehomologies are however extremely hypothetical.
In the lower forms they are not always fully differentiated, but in nearly all cases their homologiescan be readily traced.
The history of the arbitrary circumstances that were responsible for the development of each one of these homologies is entirely fatal to this wholly unwarranted speculation.
The very essence of such attempts was the institution of a series of homologies and fancied analogies between dissimilar objects.
The transference to the mandrake of the properties of the cowry (and the goddesses who were personifications of the shell) and blood (and its surrogates) was facilitated by the manifold homologies of the Great Mother with plants.
These results testify how closely the human organism stands allied to lower orders of organism around; how many homologies of structure there are, and how many analogies in experience.
Next came the acknowledgment that even with all the analogies and homologies of structure, seen and unseen, there was a vast chasm between the ape and man.
In accordance with this, we find in different orders of animal life not merely analogies or resemblances in structure, but homologies or examples of complete identity of structure and function.
The same homologies stand, but the thoracic limbs of Apus must be looked upon as highly specialized instead of primitive.
In recent years, Lankester's homologies of the parts of the limbs of Apus with those of the Malacostraca have been quite generally accepted, and the appendages of the former considered primitive.
But the contest was not so much on the causes of the variation of species as on the doctrine of homologies and the unity of organization in the animal kingdom.
Besides attending to the fertilisation of the flowers he was already, in 1860, busy with the homologies of the parts, a subject of which he made good use in the Orchid book.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "homologies" in a variety of sentences. We hope that you will now be able to make sentences using this word.
