In the earthworms, for instance, we have, in every individual developed from a zygote, ova and spermatozoa developing in different gonads in different parts of the body.
He claims by transplantation of the gonads in young rats and guinea-pigs to have feminised males and masculised females.
By what means are these effects brought about, what is the physiological explanation of the influence of the gonadson the soma?
This seems to imply a serious misunderstanding of the idea of the action of the hormones from the gonadsand of hormones in general.
The consideration of the subject involves two questions: (1) What are the exact effects of the removal of the gonads in male and female?
Here, however, we are more especially concerned with the gonads and other reproductive organs.
The gonads are not actually penetrated, at least in some cases, by the fibrous processes of the parasite, but nevertheless they are atrophied and almost disappear.
This seems so very improbable that it suggests a doubt whether the same investigator was not mistaken with regard to the results of his experiments in transplanting gonads in Moths.
In Lepidoptera among insects the evidence concerning castration tends to prove that hormones from the gonads play no part at all in the development of somatic sexual characters.
This fact, together with a number of others, make clear that while the gonads may be the jeune premier of the drama, the vitality of the plot depends upon the other endocrines.
So one may list: Infancy as the epoch of the thymus Childhood as the epoch of the pineal Adolescence as the epoch of the gonads Maturity as the epoch of whatever gland is left in control as the result of the life struggle.
Mumps may achieve the same results because of the inflammation of the gonads that may accompany or follow it.
With the advent of the gonads upon the scene, judgments become the centre of the play's plot undoubtedly.
These traits appear only when the hormones occur which are present in one sex and that only when the gonads of that sex are mature.
As regards the remaining organs of the Amphioxus, we need only mention that the gonads or sexual glands are developed very late, immediately out of the inner cell-layer of the body-cavity.
The chief advances were the formation of gonadsand nephridia, and of the rudimentary brain.
This olfactory tube would afterwards become the nervous centre, while the expanding gonads (lying to right and left of the primitive mouth) would form the coeloma.
Behind are a pair of simple sexual glands or gonads (Figure 2.
The gonads are among the oldest organs, the few other organs that we find in the Platodes between the gut-wall and body-wall being later evolutionary products.
Birds with enlarged gonadswere taken by the NAMRU2 party in March and July.
Coultas found that a large number of birds taken in November had enlarged gonads, especially the males; in December, fewer birds with swollen gonads were obtained.
In birds taken by Coultas in November the gonads were beginning to enlarge; specimens taken in December had swollen gonads.
Adult birds with enlarged gonads were taken in April, May, June, and July.
Coultas, in November and December of 1931, obtained birds with enlarged gonads at Palau.
The condition of the gonads in specimens obtained indicates that the breeding season is principally in the fall and winter.
McElroy of the NAMRU2 party obtained specimens with enlarged gonads at Truk in December and noted that birds were carrying nest materials to cane swamps.
A male with enlargedgonads was taken by the NAMRU2 party at Guam on June 7.
Of the seven specimens obtained by him, two males and one female had enlarged gonads (Dec.
The gonads are pink in the males, and yellow in the females.
The gonads of the female contain eggs; those of the male, sperms.
The dates given to gonads were, in all instances, the dates when the specimens were killed.
Stomachs and gonads were removed and preserved by standard techniques soon after specimens were killed.
Two males in advanced molt but with enlarged gonads were taken on August 9 and 10 and seem to be the first records indicating breeding in this species on Isla Cozumel.
No young Cave Swallows were taken and gonads of adults were in various stages of reproductive activity.
Gonads in our adults were moderately active; feathers were extremely worn, but molting was not evident.
Males taken on July 15 and on August 14 had fully enlarged testes; the gonads of several other specimens were apparently regressing, two specimens had begun to molt, and juveniles were molting into first winter plumage.
Gonads were moderately active in our specimens as early as mid-July.
All specimens had thick layers of subcutaneous and visceral fat and their gonads were small and seemingly inactive.
The regressing gonads of the male taken on July 21 in an early stage of molt suggests breeding on the peninsula.
The species was abundant around the cenotes at Chichen-Itza; adults with enlarged gonadsand brood patches and juveniles were taken at Piste as late as July 21.
The gonads were moderately enlarged in several of the specimens taken in the first half of July.
This is a very great departure from birds, rats and guinea pigs, whose bodies change over their sex type when the gonads are transplanted.
The bodily peculiarities of each sex, as distinguished from the sex-glands or gonads themselves, are known as secondary sex characters.
Cunoctantha fowleri Browne, buds are formed from the sub-umbrella on the under side of the stomach pouches, where later the gonads are developed.
It buds medusae from the margin of the mouth in May and June, and in August and September the gonads are formed in the place where the buds arose.
Amphogona, hermaphrodite, with male and female gonads on alternating radial canals.
There is, however, no evidence whatever for this, the gonads of Hydra being purely ectodermal structures, while all medusoid gonophores have an endodermal portion.
The gonads are on the radial canals or on the stomach (Ptychogastridae), and each gonad may be divided into two by a longitudinal sub-umbral muscle-tract.
The gonads are developed typically beneath the radial canals or below the stomach or its pouches, often stretching as long bands on to the base of the manubrium.
The gonads (g) are produced on the manubrium, which has a hollow endodermal axis, termed the spadix (sp.
Four or six radial canals; gonads band-like; stomach prolonged into a manubrium of great length; tentaculocysts enclosed.
F, G, H), and consists of the spadix bearing the gonads covered by a single layer of ectoderm (ex.
If we accept the view that Hydra is a true sexual polyp, and that its gonads are not gonophores (i.
Gonads limited in number of pairs, testes and ovaries always present in the same individual.
The segments occupied by the gonads are fixed, and are for earthworms invariably X, XI, or one of them for the testes, and XIII for the ovaries The position varies in the aquatic Oligochaeta.
The gonads are, moreover, limited and fixed in numbers, and are practically invariably attached to the intersegmental septa, usually to the front septum of a segment, more rarely to the posterior septum.
It seems that the posterior nephridia are mainly gonad ducts, and the gonads are developed in close association with the funnels.
The intervening segments contain the genitalia, which are on the Oligochaeta plan in that the gonads are independent of their ducts and that there are special spermathecae, one pair.
To this pericardial coelom is frequently added a gonocoel enclosing the gonadsand the funnels of their ducts.
Gonads not so restricted in position as in Oligochaets, and often more abundant; the individuals usually unisexual.
In Syllis there is also a "Heterosyllid" form in which the gonads are limited to a posterior region of the body which is further marked off from the anterior non-sexual segments by the oak-like setae.
The two ducts continuous with the gonads open by a common vagina on to the exterior behind the male pores.
The gonads and their ducts in the Hirudinea invariably form a closed system of cavities entirely shut off from the coelom in which they lie.
These segmental gonads are originally nothing else than the real gonotomes, separate body-cavities, formed from the hyposomites of the trunk.
The gonads are the most important segmental organs of the hyposoma, in the sense that they are phylogenetically the oldest.
As the first traces of the gonads make their appearance in the lining of these middle plates nearer inward (or the middle) from the inner funnels of the nephro-canals, it is better to count this part of the mesoderm with the hyposoma.
These segmental pairs of gonads are the original ventral halves of the coelom-pouches.
This cenogenetic process is so old that the cavity seems to be unsegmented from the first in all the craniotes, and the rudiment of the gonads also is almost always unsegmented.
Janda found that if the anterior parts containing the gonads of these worms are cut off a complete regeneration takes place, including both types of gonads, ovaries as well as testes.
Here no doubt concerning the sex was possible since the gonads were well-developed testicles containing a large number of spermatozoa of normal appearance, and no eggs.
By hermaphroditism is meant the existence of complete and separate sets of female and male gonads in the same individual.
The writer has recently examined the gonads of a ten months old parthenogenetic frog.
In the interstices of this syncytium the gonads were placed, and at first, doubtless, the life of the host ended when all the germ-cells had been set free.
In both animals an atrial cavity exists which is formed by pleural folds, and in these pleural folds thegonads are situated so that the similarity of the two branchial chambers seems at first sight very complete.
It does not seem to me possible to conceive of the gonads arising from cells of the epiblast or of the hypoblast, in the sense that such cells are differentiated cells belonging to a layer with a definite meaning.
We may suppose the first coelom to have originated by a closing or shutting off of that portion of the general archenteron of Enterocoela (Coelentera), in which the gonads developed as in Aurelia or as in Ctenophora.
The elaboration of the host means the differentiation of the protoplasm into epithelial, muscular, and nervous elements, by means of which the gonads were carried further afield and their nourishment as well as that of the host ensured.
The gonads must stand in a category by themselves; they represent a whole, {476}while the other cells represent only a part; they cannot therefore be derived from the latter.
The gonads open into the kidneys and the right gonad extends into the mantle.
The gonads of Anodonta are placed in distinct male and female individuals.
The gonads always have their own proper external apertures.
Gonads contained in the visceral mass and generally open into renal cavities.
The gonads themselves are extremely simple arborescent glands which open to the exterior by two simple ducts, one right and one left, continuous with the tubular branches of the gonads.
Gonads generally extend into mantle and open at sides of kidneys.
In the most primitive Lamellibranchs there is no separate generative aperture but the gonads discharge into the renal cavity, as in Patella among Gastropods.
Follicles of the hermaphrodite gonads of Euthyneurous Gastropods.
Even so, the season was late at the time when we were on the island and most of the birds were molting; it is possible their gonads had been enlarged earlier in the season.
The gonads of these birds were not in full breeding condition, but it is highly probable that the birds were members of a population that had bred in the area.
The gonads originate by proliferation of the anterior wall of the pericardium.
The gonads are paired and hermaphrodite, they form a pair of anterior prolongations of the pericardium, extending nearly to the anterior end of the body.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "gonads" in a variety of sentences. We hope that you will now be able to make sentences using this word.
