Now this progressive inheritance by higher types of embryological characters common to lower types is a fact which tells greatly in favour of the theory of descent, whilst it seems almost fatal to the theory of design.
As an example of the utility and, indeed, the necessity of applying the embryological method Huxley takes the case of the quadrate bone in birds.
The former view is historically prior, and arose directly out of the brilliant embryological investigations of A.
We saw that Geoffroy recognised the importance of studying the ossification of the skeleton, and that Cuvier accepted such embryological evidence as an aid in determining homologies.
What interests us chiefly in the work of this embryological period is, of course, the relation of embryology to comparative anatomy and to pure morphology.
In the last phrase we may perhaps read the first recognition of the embryological criterion.
It is impossible to say whether the paired or the unpaired condition is the more primitive, general morphological conditions being in favour of the latter, while embryological evidence rather supports the former.
While it is of the utmost importance to pay due attention to embryological data it is equally important to consider them critically and in conjunction with broad morphological considerations.
The present work by Professor Weismann, well known for his profound embryological investigations on the Diptera, will appear, I believe, to every naturalist extremely interesting and well deserving of careful study.
Experiments on the origin of species have very little value, as I said before; and this is generally true of embryological experiments also.
The embryologist Keibel is the most curious of these, as he has himself afforded a good many proofs of the biogenetic law in his careful descriptive-embryological works.
There are certain rare abnormalities of the uterus through imperfect embryological development, and pregnancy in such a uterus may result in symptoms like those of ectopic gestation.
So far as the essential processes are concerned, the embryological cells act as do the adult cells.
Sometimes this embryological cellular material starts to grow after the manner of a cancer, and then it is very malignant (syncytioma malignum), but its connection with the pernicious vomit of pregnancy is more theoretical than established.
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 cannot enter here into a discussion of the complicated anatomical and embryological relations of these structures.
This anatomical knowledge is of extreme importance; and it is supplemented by the embryological discovery that each of the higher multicellular organisms is developed out of one simple cell, the impregnated ovum.
Ten years after Baer had given a firm foundation to embryological science by his theory of germ layers a new task confronted it on the establishment of the cellular theory in 1838.
In the other classes of Arthropoda we have more or less complete embryological evidence on the subject.
The embryological facts do not appear to be in favour of these interpretations.
Embryological Studies on Diplex, Perithemis, and the Thysanurous genus Isotoma.
The embryological questions requiring to be settled concern the value of the above stages.
Up to the present time our embryological knowledge is mainly confined to a series of observations by Salensky on Brachionus urceolaris, and to scattered statements on other larval forms by Huxley, etc.
The view of Morse, that the Brachiopoda are degraded tubicolous Chaetopods, is not so far supported by any definite embryological facts.
The difficulty of deciding this point on embryological evidence depends on the fact that ontologically a tentacle and a true bud arise in the same way, viz.
The embryological facts are opposed to the view that the prae-oral region either represents a segment or is composed of segments equivalent to those of the trunk.
This tendency is probably to be regarded as the embryologicalrepetition of that phase in the evolution of the Metazoa, which constituted the transition from the protozoon to the metazoon condition.
We are therefore fairly entitled to conclude from the embryological evidence that the pen-sack of Cephalopoda is identical with the shell-gland of other Mollusca.
My aim in writing this work has been to give such an account of the development of animal forms as may prove useful both to students and to those engaged in embryological research.
The embryological record is almost always abbreviated in accordance with the tendency of nature (to be explained on the principle of survival of the fittest) to attain her ends by the easiest means.
As a consequence of this, the embryological record, as it is usually presented to us, is both imperfect and misleading.
Two very different views have been taken as to the nature of the various component parts of the Siphonophora, and the embryological evidence has been appealed to by both sides in confirmation of their views.
This comprehensive statement was rendered possible by the embryologicalresearches of Remak at the outset, and afterward by those of His and Waldeyer.
This opinion has been adopted by Mr. Packard[69] in his "Embryological Studies on Hexapodous Insects.
His patient investigations showed him that the development of the teeth commences partly in the uterus and partly after birth, which is perfectly true, as was made clear by later embryological researches.
This passage gives us an idea of the state of embryological knowledge of those days!
In order to appreciate this important feature, we have distributed the embryologicalphenomena in two groups, palingenetic and cenogenetic.
Here we find a number of complicated structures that cannot be understood until we have studied them on the embryological side in the next chapter (cf.
The larger and the detailed structure, the action, and the embryological development of the sexual organs are just the same in man as in the apes.
We are thus in a position to form a fairly complete idea of the past development of man's ancestors within the vertebrate stem by putting together and comparing the embryological developments of the various groups of vertebrates.
It will produce a great effect both by the breadth of its general views and by the extreme sagacity of its special embryological observations.
Having passed the greater part of last winter in Florida, where I was especially occupied in studying the coral reefs, I had the best opportunity in the world for prosecuting my embryological researches upon the stony corals.
So far from having put forward a theory which runs counter to the principles of embryology, I claim to have vindicated the great Law of Recapitulation which is the foundation-stone of embryological principles.
Now, from an embryological point of view, the vertebrate shows that it is a segmented animal by the formation of somites, which consist of a series of divisions of the coelom, of which the walls form a series of muscular and skeletal segments.
What, then, is the interpretation of these various embryological and anatomical facts?
This tube is the embryological expression of the simple dilated cephalic stomach, with its ventral oesophagus and two anterior diverticula, which opens into the straight intestine of the arthropod.
In fact the embryological evidence of the double segmentation in the head and the whole nature of the cranial segments is one of the main foundation-stones on which the whole of my theory rests.
My theory, on the other hand, is in perfect harmony with the embryological history, and explains it point by point.
Such facts should stimulate all our young students to embryological investigation as a most important branch of study in the present state of our science.
Yet, although there is no embryological transition of one type into another, the gradations of growth within the limits of the same type and the same class, already alluded to, are very striking throughout the Animal Kingdom.
The truth is that the hymen is a worse-than-useless relic of embryological development, and it is neither an indicator nor a dictator of morality.
The ideal way for giving a popular glimpse at human development is with a small series of lantern slides or photographs from embryological works.
The embryological facts of human biology are very impressive to boys and young men who know little of science.
Sir John Lubbock also insisted on the embryological evidence for evolution.
You are right again, if you view the matter only from an embryological or psychological standpoint.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "embryological" in a variety of sentences. We hope that you will now be able to make sentences using this word.
