The homologous tumor appears rather as a hypertrophy of the tissue from which it arises, and the line between this variety of growth and a simple hypertrophy is often purely arbitrary.
There is produced from it, as a neoplasm, either a tissue which follows the type of the maternal tissue, a homologous tumor, or one which deviates in type from that of the matrix, a heterologous growth.
These corresponding parts are called, in the technical language of anatomy, "homologous parts.
Morphology has taught us that it is a series of segments composed of homologous parts, which undergo various modifications--beneath and through which a common plan of formation is discernible.
This relationship between the members of homologous series is expressed in other terms by saying that the weight of the molecule increases by a constant quantity as we ascend the series.
If, therefore, the supposition that the appendages on the antennae of the pupae of Rhizocephala are young roots be correct, the roots of the Rhizocephala are homologous with the cement-ducts of the Cirripedia.
Parts homologous in this sense might develop in different ways, but no great importance was to be attached to such a circumstance.
Coelentera were homologous with the ectoderm and endoderm of the germ was thus fully confirmed and greatly extended.
They are serially homologous with, for example, the uncinate processes of the ribs in birds (see Figs.
It is interesting to note that in developing this idea he arrived at a roughly accurate distinction between homologous and analogous structures.
Generally speaking, parts which bear the same name are for Aristotle homologous throughout the class.
It is certainly the case that Spix published before Geoffroy the view that the opercular bones are homologous with the ear-ossicles, adopting, however, a different homology for the separate bones.
The unpaired sternal bone (urohyal) cannot be homologous with the entosternal, for it has no connections with the annexes.
Thus the bones of the upper arm are completely homologous throughout all vertebrate classes from Amphibia upwards, while the heart of a fish is incompletely homologous with the heart of a mammal.
In other respects Sedgwick's speculations link on more closely to the Gastræa theory, for one of his main contentions is that the blastopore or Urmund is homologous throughout at least the three metameric phyla.
The main assumption was that the neural or blastoporal surface must be homologous throughout the Metazoa, though it was dorsal in the Chordata, ventral in the Annelida and Arthropoda.
These muscles are striae-less, which is the case with the homologous posterior thoracic muscles in some other cirripedes: on the dorsal surface (lower surface in fig.
The little transverse crenations are homologous with the septa in the radii and parietes.
The last-formed slip of membrane over a suture is homologous with the opercular membrane; and both are strictly analogous with the ring of flexible membrane, forming the joint of the leg of a crab.
These septa, as well as the radiating ridges in the case of the single lamina, are homologouswith the longitudinal septa of the parietes.
These fibres enter a little way within the lobed peduncle; they are probably homologous with the strong muscles, which run from beneath the upper end of the horny disc of the female to the lower end of the orifice leading into the sack.
The fixed scutum is larger than the fixed tergum, and therefore has the same proportions as the homologous valves in ordinary cirripedia, but reversed proportions compared with the moveable scutum and tergum.
There must be a nervous system; and there must likewise be a gland (homologous with the ovaria) for secreting the cement; but I could not distinguish parts so small.
The other is that the rings of fruit-scars on the branches of Sigiliaria are homologouswith leaf-scars, not with branches, and therefore should have borne single carpels and not cones or spikes of inflorescence.
Gegenbaur[72] has argued from the resemblance of these appendages to wings, that the wing and the tracheal leaflet are homologous parts, and this view has been accepted as probable by so competent an observer as Sir John Lubbock.
The behaviour ofhomologous twinning in heredity has been little studied.
There is a perfect series of gradations connecting them with the various forms of double monsters united by homologous parts.
Such values were converted to percentage values, that of the homologous reaction being considered 100 per cent.
Homologous reactions are arbitrarily valued as 100 per cent, and heterologous reactions are expressed accordingly.
Furthermore, the magnitudes of the reactions between the antiserum and the heterologous antigens vary according to the degrees of similarity of these antigens to the homologous one.
The homologous reaction was the standard of reference for all other test reactions with the same antiserum.
This point is illustrated further by a test (not illustrated) involving Zonotrichia querula (the homologous antigen) and Zonotrichia albicollis.
In this case also each pair would be formed by two homologous chromosomes, the one of paternal, the other of maternal origin.
I believe further that homologous conceptions are applicable in the consideration of the transmutations of the various forms of animal and of vegetable life and in other regions of thought.
It follows from these phenomena that any exchange which may be effected must be one of homologous carriers of hereditary units only.
It seems probable that these are homologous chromomeres, and that the pairs afterwards unite for a short time, so that an exchange of hereditary units is rendered possible.
In the reduction nucleus of the gonotokonts the homologous chromosomes being near together need not seek out one another; they are ready to form gemini.
Clearly an interchange has taken place between the two X chromosomes in the female in such a way that a piece of one chromosome has been exchanged for the homologous piece of the other.
They can occur only through a new lethal arising through mutation in the homologous chromosome of a female that already carries one lethal.
In such a case the factors might be said to be completely linked, yet each would be supposed to have its normal allelomorph in the homologous chromosome of the wild type.
When the homologous chromosomes come together at synapsis it has been demonstrated, in some forms at least, that they twist about each other so that one chromosome comes to lie now on the one side now on the other of its partner.
The scales of the bud of Horsechestnut are considered to be homologous with petioles, by analogy with other members of the same family.
Other examples of scaleshomologous with stipules are the American Elm, Tulip-tree, Poplar and Magnolia.
X Onions and Orchids "The perimeters of similar polygons are as their homologous sides.
She obligingly furnished a sample: "The perimeters of similar polygons are as their homologous sides.
Spiders are provided at the posterior end with two or three pairs of appendages called spinnerets, which are homologous (correspond structually) [tr.
The whale and the elephant both have backbones, jointed limbs, warm blood, and a hundred homologous organs.
The tympanic chain of higher vertebrates has been thought homologous with the suspensory of the mandible.
It has a row of ventral plates like those of Birkenia, the only other hard parts it possesses being a number of parallel rods behind the head, homologous with the lateral series of Birkenia.
The name 'coracoid,' originally applied to the process so called in the human scapula and subsequently extended to the independent elementhomologous with it in birds and other vertebrates, has been more especially retained (e.
Comparative embryology makes it almost certain that the subneural gland with its duct, described above, is homologous with the hypophesis cerebri of true vertebrates, and that the endostyle is homologous with the thyroid glands of vertebrates.
The hyomandibular is thought to be homologous with the stapes, or stirrup-bone, of the ear in higher animals.
The coracoid of Polypterids is also evidently homologous with the corresponding element in the other Ganoids, and the latter consequently must be also coracoid.
As this compound bone, composed of the scapula and ectocoracoid fused together, has received no name which is not ambiguous or deceptive in its homologous allusions, it may be designated as proscapula.
In a general way the skeleton of the fish is homologous with that of man.
In this case the symplectic may be homologous with its small orbicular bone, and the malleus is a transformation of the articular.
These teeth are much larger and much less sharp than in the sawsharks, but they are certainlyhomologous with these, and the two groups must have a common descent, distinct from that of the other rays.
But it is evident that the external elements of the so-called carpus of the teleosteoid Ganoids are homologouswith that element in Polypterids.
In some bony fishes as the eels and female salmon the germ cells are shed into the body cavity and escape through genital pores, which, however, may not be homologous with abdominal pores.
This little bone has been called coronoid, but it is doubtless nothomologous with the coronoid bone of reptiles.
There can be no doubt, therefore, that the pharyngeal sac of Ascidians is homologous with the pharynx of fishes.
The proximal element of the anterior limb in the Dipnoi has almost by common consent been regarded as homologous with the humerus of the higher vertebrates.
One of the higher alcohols of the methane series, homologous with ethal, and found in small quantities as an ethereal salt of stearic acid in spermaceti.
Diversified homologousforms made to fulfill analogous functions, or special purposes fulfilled whilst maintaining a general plan, indicating choice and alternativity.
On the one hand, we meet with structures which are perfectlyhomologous and yet in no way analogous: the structural elements remain, but are profoundly modified so as to perform wholly different functions.
We can see by the wood-cuts that it presents a series of gill-slits, like the homologous parts of the fishes with which it is compared--i.
Homologous structures are particularly liable to change together, as we see on the opposite sides of the body, and in the upper and lower extremities.
Turner informs me, is undoubtedly homologous with the spinal cord; but the lower part apparently consists merely of the pia mater, or vascular investing membrane.
The latera overlie the carinal half of the terga; I presume that they are homologous with the carinal latera in Scalpellum.
The roughened knobs at the rostral angles of the scuta, no doubt are homologous with the teeth in a similar position on one or both scuta in Lepas, and in some fossil species of Pollicipes, as in P.
I believe that it is strictly homologous with the fold, over which the complemental male is attached in S.
A layer of chitinehomologous with the shell, and partially lining the scutum.
The areas of similar polygons are to each other as the squares of the homologous sides of the polygons.
If the homologous crests of two contiguous faces do not meet each other, they should be reconciled by joining two points taken on each of them at half a meter from the intersection of their projections.
The volumes of two similar polyhedrons are to each other as the cubes of the homologous edges.
They are also similar if two faces of the one, making with each other the same angle as two faces of the other, are also similar to these latter, and are united by homologous sides and summits.
The homologousedges of similar polyhedrons are proportional; as are also the diagonals of the homologous faces and the interior diagonals of the polyhedrons.
When the triangles which form two homologous trihedral angles of two tetrahedrons are similar, each to each, and similarly disposed, these tetrahedrons are similar.
The perimeters of two similar polygons are to each other as the homologous sides of these polygons.
The right lines similarly situated in the two polygons are proportional to the homologous sides of the polygons.
The areas of similar polyhedrons are as the squares of the homologous edges.
