In some cases (many species of Ascaris) the metamorphosis is reduced to a simple process of growth.
- Stages in the fixing and metamorphosis of Terebratulina.
The weight of Malpighi's observations therefore fell into the scale of that doctrine which Harvey terms metamorphosis, in contradistinction to epigenesis.
He thus views the consecration of the elements as akin to other consecrations; and, like priestly ordination, as involving " a metamorphosis for the better," a phrase which later on became classical.
The freeliving differ from the majority of the parasitic forms in undergoing no metamorphosis; they also possess certain structural peculiarities which led Bastian (Trans.
Much consideration has been given to the nature of metamorphosis in insects, to its value to the creatures and to the mode of its origin.
Lubbock (Lord Avebury), Origin and Metamorphosis of Insects (London, 1874); L.
A common result of metamorphosis is that the larva and imago differ markedly in their habitat and mode of feeding.
Miller discovered that they undergo a metamorphosis, and that the minute worm-like lamperns previously known under the name of Ammocoetes, and abundant in the sand and mud of many streams, were nothing but the undeveloped young of the river-lampreys and small lamperns.
The differences in appearance between the caterpillar and the butterfly, striking as they are to the eye, do not sufficiently represent the phenomena of metamorphosis to the intelligence.
The ciliated larva escapes from the egg into the water and enters an intermediate host (leech, mollusc, arthropod, batrachian or fish) where it undergoes a metamorphosis into a second stage in which most of the adult organs are present.
These Polystomum deposit their eggs in the branchial chamber and die at the metamorphosis of their host.
The fascinating difficulties presented to the student by the metamorphosis of the Hexapoda are to some extent explained, as he ponders over the evolution of the class.
In the Metanemertini, as far as they have been investigated, a direct development without metamorphosis has been observed.
Direct development, in which the adult form is achieved without striking metamorphosis by a gradual succession of stages, seems to be confined to the family Balanoglossidae.
The story of Lohengrin as we know it is based on two principal motives common enough in folklore: the metamorphosis of human beings into swans, and the curious wife whose question brings disaster.
(I) the larger part of the hypodermis that exists in the maggot or caterpillar and is disf e b solved at the metamorphosis; (2) parts that remain comparatively quiescent previously, and that grow and develop when the other parts degenerate.
Moreover, in many insects with imperfect metamorphosis the change from larva or (as the later stage of the larva is called in these cases) nymph to imago is about as great as the corresponding change in the Holometabola, as the student will recognize if he recalls the histories of Ephemeridae, Odonata and male Coccidae.
This is a most remarkable case, but unfortunately very little information exists as to the details of metamorphosis in this group.
It appears.probable that this is only a further simplification of the more complicated metamorphosis described above.
As regards growth after hatching, all beetles undergo a "complete" metamorphosis, the wing-rudiments developing beneath the cuticle throughout the larval stages, and a resting pupal stage intervening between the last larval instal1 and the imago.
This migration is usually accompanied by a more or less complete metamorphosis.
the bionomic nature of metamorphosis, and to what extent it existed in primitive insects.
Meanwhile the English naturalist, John Ray, was studying the classification of animals; he published, in 1705, his Methodus insectorum, in which the nature of the metamorphosis received due weight.
The formative force in this process of evolution (or " metamorphosis ") is conceived as an intellectual principle (idee generatrice).
The post-embryonic growth of Hexapods with or without metamorphosis is accompanied in most cases by the acquisition of wings.
It is now, in fact, generally admitted that metamorphosis has been acquired comparatively recently, and Scudder in his review of the earliest fossil insects states that " their metamorphoses were simple and incomplete, the young leaving the egg with the form of the parent, but without wings, the assumption of which required no quiescent stage before maturity."
Metamorphosis in Diptera is complete; the larvae are utterly different from the perfect insects in appearance, and, although varying greatly in outward form, are usually footless grubs; those of the Muscidae are generally known as maggots.
The process of destruction of the larval tissues was first studied in the forms where metamorphosis is greatest and most abrupt, viz.
In connexion with the question whether metamorphosis has been gradually acquired, we have to consider two aspects, viz.
The word metamorphosis cannot, in fact, be used any longer in its original sense, for the change which it implied does not normally occur in ontogeny, and in phylogeny the idea is more accurately expressed by the term differentiation.
In the former position the suckers are developed and growth proceeds for 8 to Io weeks until the metamorphosis of its host.
Metamorphosis.It has already been pointed out that each kind of member of the body may present a variety of forms. For example, a stem may be a tree-trunk, or a twining stem, or a tendril, or a thorn, or a creeping rhizome, or a tuber; a leaf may be a green foliage-leaf, or a scale protecting a bud, or a tendril, or a pitcher, or a floral leaf, either sepal, petal, stamen or carpel (sporophyll); a root may be a fibrous root, or a swollen tap-root like that of the beet or the turnip. All these various forms are organs discharging some special function, and are examples of what Wolff called modification, and Goethe metamorphosis.
Brauer in his arrangement of these orders laid special stress on the nature of the metamorphosis, and was the first to draw attention to the number of Malpighian tubes as of importance in classification.
Others again consider that the whole cycle is a metamorphosis which, beginning in the Heterocotylea as a direct development, has become complicated in the Holostomidae by a larval history, and finally in the Malacocotylea has acquired additional complexity by the intercalation of two larval forms, and is thus spread over several generations.
The wingless forms in question are always allied to winged forms, and there is every reason to believe that they have been really derived from winged forms. There are also insects (fleas, &c.) in which metamorphosis of a " complete " character exists, though the insects never develop wings.
In the latter respect, and in the fact that they frequently develop by a metamorphosis, they approach the Mollusca, but they differ from that group notably in the occurrence of metameric segmentation affecting many of the systems of organs.
Metamorphosis is, from this point of view, the sum of the changes that take place under the cuticle of an insect between the ecdyses, which changes only become externally displayed when the cuticle is cast off.
Amongst insects with imperfect metamorphosis the nearest approximations to the true pupa of the Holometabola are to be found in the subimago a From Chittenden, Bull.
Insect metamorphosis may be briefly described as phenomena of development characterized by abrupt changes of appearance and of structure, occurring during the period subsequent to embryonic development and antecedent to the reproductive state.
The Siphonaptera appear by the form of the larva and the nature of the metamorphosis to be akin to the Orthorrhapha - in which division they have indeed been included by many students.
He has observed that in young specimens of Siren lacertina (the larva is still unknown) the gills are rudimentary and functionless, and that it is only in large adult specimens that they are fully developed in structure and function; he therefore concludes that the sirens are the descendants of a terrestrial type of batrachians, which passed through a metamorphosis like the other members of their class, but that more recently they have adopted a permanently aquatic life, and have resumed their branchiae by reversion.
His cult survived the metamorphosis of the ancient Vedic nature-worship into modern Hinduism, and there still are in India fire-priests (agnihotri) whose duty is to superintend his worship. The sacred fire-drill for procuring the temple-fire by friction - symbolic of Agni's daily miraculous birth - is still used.
The order of the Hemiptera affords, ` therefore, some interesting transition stages towards the complete metamorphosis of the higher insects.
The eruciform larva of the Orthorrhapha leads on to the headless vermiform maggot of the Cyclorrhapha, and in the latter sub-order we find metamorphosis carried to its extreme point, the muscid flies being the most highly specialized of all the Hexapoda as regards structure, while their maggots are the most degraded of all insect larvae.
Both agree in having nothing that can be termed a metamorphosis; they are active from the time of their exit from the egg to their death, gradually increasing in size, and undergoing several moults or changes of skin.
The other groups of the old Linnean order (such as lacewing-flies and caddis-flies)--which are hatched as larvae markedly unlike the parent, develop wing-rudiments hidden under the larval cuticle, and only show the wings externally in a resting pupal stage, passing thus through a " complete " metamorphosis and falling into the sub-class Endopterygotawere retained in the order Neuroptera, which thus became much restricted in its extent.
Bionomically, metamorphosis may be defined as the sum of adaptations that have gradually fitted the larva (caterpillar or maggot) for one kind of life, the fly for another.
Living matter, or protoplasm and the products of its metamorphosis, may be regarded under four aspects: r.
The remaining two families of Enteropneusta, Ptychoderidae and Spengelidae, contain species of which probably all pursue an indirect course of development, culminating in a metamorphosis by which the adult form is attained.
and very frequently some of these tentacles have undergone a special metamorphosis converting them into highly-organized eyes.
The insects retained in the order Neuroptera as restricted by modern systematists are distinguished from the preceding orders by the presence of a resting pupal stage in the life-history, so that a " complete metamorphosis " is undergone.
A dragonfly goes through a metamorphosis period just like a butterfly.
A natural system must take into account the nature of the larva and of the metamorphosis in conjunction with the general characters of the imago.
- Diagrams illustrating the Metamorphosis of Actinotrocha.
The epistome of the adult Phoronis cannot well be the proboscis since its cavity is continuous with the lophophoral coelom, and because the praeoral hood of Actinotrocha is entirely lost at the metamorphosis.
Her magic prodded him, and she saw the same trace of metamorphosis that had marked Darian the past few weeks.
metamorphosis of insects, for example in the birth of butterflies.
extreme metamorphosis) is a comparatively recent phenomenon of insect life.
Fleas are oviparous, and undergo a very complete metamorphosis.
Although several species belonging to the second class occasionally enter the bodies of water snails and other animals before reaching their definitive host, they undergo no alteration of form in this intermediate host; the case is different, however, in Filaria medinensis and other forms, in which a free larval is followed by a parasitic existence in two distinct hosts, all the changes being accompanied by a metamorphosis.
Those who were unwilling to accept evolution, without better grounds than such as are offered by Lamarck, and who therefore preferred to suspend their judgment on the question, found in the principle of selective breeding, pursued in all its applications with marvellous knowledge and skill by Darwin, a valid explanation of the occurrence of varieties and races; and they saw clearly that, if the explanation would apply to species, it would not only solve the problem of their evolution, but that it would account for the facts of teleology, as well as for those of morphology; and for the persistence of some forms of life unchanged through long epochs of time, while others undergo comparatively rapid metamorphosis.
These modifications are mentioned below in the section on metamorphosis.
Growth and Metamorphosis.
undergoing metamorphosis (7).
One of Harvey's prime objects is to defend and establish, on the basis of direct observation, the opinion already held by Aristotle, that, in the higher animals at any rate, the formation of the new organism by the process of generation takes place, not suddenly, by simultaneous accretion of rudiments of all or the most important of the organs of the adult, nor by sudden metamorphosis of a formative substance into a miniature of the whole, which subsequently grows, but by epigenesis, or successive differentiation of a relatively homogeneous rudiment into the parts and structures which are characteristic of the adult.
Similar views were arrived at by Goethe, though by the deductive rather than the inductive method, and were propounded in his famous pamphlet, Versuch die Metamorphose der Pfianzen zu erklren (1790), from which the following is a quotation: The underlying relationship between the various external parts of the plant, such as the leaves, the calyx, the corolla, the stamens, which develop one after the other and, as it were, out of one another has long been generally recognized by investigators, and has iii fact been specially studied; and the operation by which onc and the same organ presents itself to us in various forms has been termed Metamorphosis of Plants.
At the metamorphosis, this sac is everted and the alimentary canal is drawn into it in the form of a loop (fig.
While no single event or time frame indicates the end of childhood and the start of adulthood, some very significant changes take place indicating this metamorphosis has begun.
Hilary Duff's second album, Metamorphosis (2003), introduced hits like "So Yesterday" and "Come Clean," both of which landed squarely on the top 40.
Although the original monokini never quite caught on, it has gone through a fashion metamorphosis.
Through the amazing process of metamorphosis it comes back into the world, emerging from its shell as a beautiful, free-fluttering and graceful butterfly.
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Change: The most obvious meaning is change or metamorphosis.
Owing to more or less herbivorous habits, the intestine is exceedingly elongate and much convoluted, being several times larger and of a greater calibre than after the metamorphosis.
The phylogeny of the various floral leaves, for instance, was generally traced as follows: foliage-leaf, bract, sepal, petal, stamen and carpel (sporophylls)in accordance with what Goethe termed ascending metamorphosis.
from sporophylls); that is, they are the result of descending metamorphosis.
In such cases the development of wings and the attainment of the adult form depend upon a more or less profound transformation or metamorphosis.
The new instar - or temporary form - is often very different from the old one, and this is the essential fact of metamorphosis.
The unlikeness of the young insect to its parent is one of the factors that necessitates metamorphosis.
None of the groups of existing Endopterygota have been traced with certainty farther back than the Mesozoic epoch, and all the numerous Palaeozoic insect-fossils seem to belong to forms that possessed only imperfect metamorphosis.
Both Hetero- and Metane- mertini have been more exhaustively studied than the other two groups, the first, as was noticed above, being characterized by peculiar larval forms, the second developing without metamorphosis.
Two pairs of invaginations of B the skin, which originally are called the prostomial and metastomial disks, grow round the intestine, finally fuse together, and form the skin and mus- cular body-wall of the future Nemertine, which afterwards becomes ciliated, frees itself from the pilidium investment and develops into the adult worm without further metamorphosis.
During this period he published his poetical satire called Metamorphosis (1726), his Epistolae ad virum perillustrem (1727), his Description of Denmark and Norway (1729), History of Denmark, Universal Church History, Biographies of Famous Men, Moral Reflections, Description of Bergen (1737), A History of the Jews, and other learned and laborious compilations.
As regards their life history, all Hymenoptera undergo a " complete " metamorphosis.
Localities at such altitudes not being, as a rule, suitable for larval life in the water, the young are retained in the uterus, until the completion of the metamorphosis.
At its first metamorphosis it produces a caterpillar, then a bombylius and lastly a chrysalis - all these changes taking place within six months.
The first soma is supposed to have been stolen from its guardian demon by an eagle, this soma-bringing eagle of Indra being comparable with the nectar-bringing eagle of Zeus, and with the eagle which, as a metamorphosis of Odin, carried off the mead.
jaws under Hexapoda); in the presence of a large number of excretory (Malpighian) tubes; in the firm texture of the forewings; in the presence of appendages (cerci) on the tenth abdominal segment; and in the absence of a metamorphosis, the young insect after hatching closely resembling the parent.
When the time for eclosion has come, the male enters the water with his burden; the larvae, in the full tadpole condition, measuring 14 to 17 millimetres, bite their way through their tough envelope, which is not abandoned by the father until all the young are liberated, and complete in the ordinary way their metamorphosis.
The trunk develops on the lower surface of the disk-like larva, which undergoes a more or less sudden metamorphosis into the young worm (fig.
At the end of this time it undergoes a rapid metamorphosis: FIG.
Senn, pursuing the methods described by Klebs, has confirmed Chodat's observation of the passage of Raphidium into a Dactylococcus-stage, although he was unable to observe further metamorphosis.
While, therefore, there is much evidence of a negative character against the existence of an extensive polymorphism among algae, some amount of metamorphosis is known to occur.
When fullsized they leave the water and spend a quiescent pupal stage on the land before metamorphosis into the sexually mature insect.
To metamorphosis he only allowed a logical value, as explaining the natural classification; the only real, existent metamorphosis he saw in the development of the individual from its embryonic stage.
Of far-reaching importance was, on the other hand, his foreshadowing of the Darwinian theory in his works on the metamorphosis of plants and on animal morphology.
The animal leaves the water after completing its metamorphosis, the last stage of which is marked by the loss of the gills.
Duges's statement that there is a second species of Amblystoma, which is normal in its metamorphosis, near Mexico but at a higher altitude, which may explain Velasco's observation that regularly transforming Amblystomas occur near that city; and thirdly, he made a careful examination of the two lakes, Chalco and Xochimilco, where the axolotls occur in abundance and are procured for the market.
The adult form is achieved by metamorphosis, which cannot be further described here.
In addition to the complete absence of wings and of metamorphosis, the Aptera are characterized by peculiar elongate mandibles (figs.
Europe in fact had been prepared for a thoroughgoing metamorphosis before that new ideal of human life and culture which the Revival of Learning brought to light had been made manifest.
According to Weizsacker, he was an old Pelasgian or pre-Hellenic god, to whom human sacrifice was offered, bearing a non-Hellenic name similar to XLKo, whence the story originated of his metamorphosis into a wolf.
For the universe and all its parts are only different embodiments and stages in that metamorphosis of primitive being which Heraclitus had called a progress up and down (6561 &v i Out of it is separated, first, elemental fire, the fire which we know, which burns and destroys; and this, again, condenses into air or aerial vapour; a further step in the downward path derives water and earth from the solidification of air.
Vaughan Thompson demonstrated the existence of metamorphosis in the development of the higher Crustacea.
There are many cases, however, in which the metamorphosis is suppressed, and the newlyhatched young resemble the parent in general structure.
In the name Diomedea, assigned to them by Linnaeus, there is a reference to the mythical metamorphosis of the companions of the Greek warrior Diomedes into birds.
It might be possible to prove the origin of all classes from Pelmatozoa, without thereby explaining the origin of such fundamental features as radial symmetry, the developmental metamorphosis, and the torsion that affects both gut and body-cavities during that process; but the acceptance of a Dipleurula as the common ancestor necessitates an explanation of these features.
The difficulty of rearing the larvae in an aquarium towards the close of the metamorphosis may account for the slight information available concerning the stages that immediately follow the embryonic. Another difficulty is due to the fact that the types studied, and especially the crinoid Antedon, are highly specialized, so that some of the embryonic features are not really primitive as regards the class, but only as regards each particular genus.
These associations of individuals can hardly be the result of the metamorphosis of a corresponding number of larvae, but are probably due to a spontaneous fragmentation of the adult animals, each such fragment developing into a complete Phoronis (De Selys-Longchamps).
The relations of the surfaces after the metamorphosis are clearly very different from those which obtained in the larva.
The difficulty of mythology is to account for the following among other apparently irrational elements in myths: the wild and senseless stories of the beginnings of things, of the origin of men, sun, stars, animals, death, and the world in general; the infamous and absurd adventures of the gods; why divine beings are regarded as incestuous, adulterous, murderous, thievish, cruel, cannibals, and addicted to wearing the shapes of animals, and subject to death in some stories; the myths of metamorphosis into plants, beasts and stars; the repulsive stories of the state of the dead; the descents of the gods into the place of the dead, and their return thence.
We find, too, that political power, sway and social influence are based on the ideas of magic, of metamorphosis, and of the power which certain men possess to talk with the dead and to visit the abodes of death.
Yehl's powers of metamorphosis and of flying into the air are the common accomplishments of sorcerers, and he is a rather crude form of first father, " culture-hero " and creator.2 Among the Karok Indians we find the great hero and divine benefactor in the shape of, not a raven, nor an eagle-hawk, nor a mantis insect, nor a spider, but a coyote.
A.) box for The straw sleep. and how the lower portion allows the bees to cluster around the tender larvae and thus maintain the warmth necessary during its metamorphosis from the egg to the perfect insect.
Flowers become double by the multiplication of the parts of the corolline whorl; this arises in general from a metamorphosis of the stamens.
These three peaks are formed of eruptive rocks, surrounded by Jurassic beds which have undergone a thorough metamorphosis.
Ridewood (30), the whole hyobranchial apparatus forms a cartilaginous continuum, and during metamorphosis the branchialia disappear without a trace.
A few batrachians retain the ova within the oviducts until the young have undergone part or the whole of the metamorphosis.
Even the fossil Stegocephalia underwent metamorphosis, as we know from various larval remains first described as Branchiosaurus.
In the Caudata, external gills (three on each side) persist until the close of the metamorphosis, whilst in the Apoda and Ecaudata they exist only during the earlier periods, being afterwards replaced by internal gills.
Though she expected him to continue the rapid cycle of changes, she couldn't help feeling this metamorphosis was different.
There is a complex metamorphosis, with three larval stages, followed by a pupal stage enclosed in silken cocoon.
During pupation the larva undergoes complete metamorphosis, in which all its organs dissolve, leaving the pupa filled with fluid.
imaginal thoracic disks during Drosophila metamorphosis.
Upon reaching 10cm or more the juvenile will undergo metamorphosis.
We have a metamorphosis in terminology on our hands!
The butterfly kit allows a child to see the complete metamorphosis from larvae to butterfly, both an exciting and wonderful learning experience.
At this stage they begin the metamorphosis from a vertical life to a horizontal position.
Try your hand at finding the right simile to describe this metamorphosis.
The species follows the normal mite incomplete metamorphosis, with the female mite laying her eggs singly throughout the year.
I felt angry for about a limit of two hours and then a strange metamorphosis came over me.
Only then will a complete metamorphosis take place from the lower senses to the activities of the upper senses.
Due to the large change from larval to adult form, the insects are said to undergo complete or complex metamorphosis.
Back home, electricity is going through its own metamorphosis.
metamorphosis into a salmon fisher?
metamorphosis project is now in Stage 2 and looking forward to future developments.
metamorphosis trilogy was the most successful theme to date for Yaa.
metamorphosis simple, usually with six nymphal stages before reaching maturity, although some wingless forms may have fewer stages.
Maria Sibylla Merian ' (born in Frankfurt, 1647 1717) was the first known person to record observations on insect metamorphosis.
Its condition thus recalls the pupal instar of the higher (Endopterygote) Hexapoda; and the Thysanoptera, though few in number, are seen to be of great interest to the student, exhibiting at once a transition between the biting and the suctorial mouth, and the passage from " incomplete " to " complete " metamorphosis.
This migration is usually accompanied by a more or less complete metamorphosis, which is, however, not so conspicuous as in most other parasites, e.g.
A simple case is that of double flowers, in which the number of the petals is increased by the metamorphosis of stamens; or again the conversion of floral leaves into green leaves, a change known as chloranthy.
Growth And Metamorphosis After hatching or birth an insect undergoes a process of growth and change until the adult condition is reached.
a more or less profound transformation or metamorphosis before the perfect state is attained.
Metamorphosis among the Hexapoda depends upon the universal acquisition of wings After Howard, Insect Life, vol.
And we must infer further that the specialization of the higher orders has been accompanied by an increase in the extent of the metamorphosis - a very exceptional condition among animals generally, as has been ably pointed out by L.
There is no metamorphosis during growth such as occurs in some insects, the young being hatched with its full complement of appendages and only differing from its parents in characters of comparatively minor importance.
One view, the monozoic, regards the whole development as a prolonged metamorphosis; another, the polyzoic view, considers that not only is the Cestode a colony, the proglottides being produced asexually, but that the scolex which buds off these individuals is itself a bud produced by the spherical embryo or onchosphere.
It has, moreover, been shown (see especially Goodrich, 5) that shortly before its metamorphosis, Actinotrocha develops a coelomic space which lies immediately in front of the oblique septum, and gives rise later to the cavity of the lophophore and tentacles.
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