The immature ovaries and testes take the form of elongate oval bodies, which prolong themselves backwards into a long thin thread-like cord or ligament (figs.
In adult males the testes undergo atrophy, but can with care be discovered in the enveloping fat-body.
In Blatta germanica the testes are functional throughout life.
The atrophied testes are nevertheless sufficiently large in the adult to be easily made out.
The testes are of irregular, oval figure, the vasa deferentia very long, tortuous, and enlarged towards the middle of their length.
The testes may be found in older larvæ or adults beneath the fifth and sixth terga of the abdomen.
In the first place the testes are functional only in the young male.
The testesand associated glandular bodies gradually develop the power of forming perfect semen, capable of fertilizing the human ovum.
The liquid secretion of the testes probably does not leave the testes but is reabsorbed.
At the time of the examination only small atrophied remains of thesetestes could be discovered.
This descent of the testes from the abdomen takes place normally in the later weeks of intrauterine life.
The testes may, however, through some unusual condition, be retained and make their descent months or even years later.
It used to be supposed that the semen was secreted wholly by the testes; that the testes were secreting continuously and that the seminal vesicles were receptacles for the gradually accumulating semen from the testes.
The young man at puberty begins to receive from his testes the internal secretion which leads to the development of his full manly powers.
Physiologists have endeavored to determine exactly what substance formed by the testes is reabsorbed into the lymph and blood.
In harmony with that law, the testes secrete only under the influence of sexual stimulation.
The testes in all adult males are granular, ovoid in shape, and greatly enlarged.
In the Urodela the testes are united with the anterior part of the Wolffian body.
Human adults are occasionally found to be "testi-conde;" the testes being situated below the kidneys, or at some part between this position and the internal inguinal ring.
Footnote 2: In many quadrupeds (the Rodentia and Monotremes) the testesremain within the abdomen.
In the Elephant, the testes always occupy their original position beneath the kidneys, in the loins.
Sometimes only one of the testes descends to the scrotum.
On several occasions large males having enlarged testes were not readily rebuffed by females but continued to follow them.
In confinement only those males having markedly enlarged scrotal testes showed interest in females that were in oestrus.
Dr Anderson’s specimen showed two large oval testes placed one above the other in the middle line, and rather higher up than is usual with those distomes that have the organs presenting this simple form.
A small lobed gland immediately above thetestes is probably the ovary.
The figure in question shows that in this species the testes are globular and placed high up in the middle line of the body.
Only the merest traces of these smaller channels were visible; but the two oval testes were well defined, occupying a position somewhat lower down than usual.
Increase in length of testes appears to be correlated with length of the individual rather than cyclic reproductive periods (Fig.
The testes increase in size gradually rather than rapidly at maturity or in each breeding season, but seasonal cycles in sperm production occur.
The introduction of castration as a method of negative eugenics has been facilitated by the use of new methods of performing it without risk, and without actual removal of the testes or ovaries.
The sizes of thetestes of three of the males (6-7 mm.
The species probably nests in northern Coahuila as well; the lengths of the testes (left, 9 mm.
The vasa efferentia of the testes in Scyllium are very typical, but there are some forms in which they are more numerous as well as others in which they are less so.
The central canal of the base of the testes and the network connected with it in the adult (Pl.
It has already been stated that the semen is carried by vasa efferentia from the testes to the anterior segments of the Wolffian body, and thence through the coils of the Wolffian body to the Wolffian duct.
While its general relations are represented in my figure, the opacity of the testes was too great to allow of all the details being with certainty filled in.
The presence of vasa efferentia in the male carrying the semen from the testes to the kidney, and through the tubules of the latter into the kidney duct.
Mr Haddon, are shewn the vasa efferentia and their junctions both with the testes and the kidney.
The testes are placed at different levels in the median compartment of the body-cavity, and both lie on the same side of the intestine (right side).
We also occasionally meet cases of human beings in which the testes have never descended from their place in the abdominal cavity, giving the individuals the appearance of eunuchs.
Here is now established a permanent source of irritation, by which the morbid activity of the testes and seminal vesicles is kept up and continually increased.
Men from whom the testes have been removed before puberty, as in the case of eunuchs, are never fully developed as they would otherwise have been.
This operation consists in the removal of the testes of the male.
In another male both testes were shrunken and discolored and appeared to be encased by fibrous tissue.
Seasonal fluctuations in size (average greatest diameter) oftestes in T.
The testes are smallest in spring and largest in September.
The testes of specimens that were nearly mature contained primary and secondary spermatocytes but lacked lumina; it was thought that such individuals would have matured in the following summer and bred in the following autumn.
The histological appearance oftestes preserved in April and May is much the same.
Recession of testes in spring was coincident with the period of active breeding; increase in size, later in the season, corresponded to increasing spermatogenic activity and enlargement of seminiferous tubules.
Testes are smallest in April, immediately after emergence from hibernation, and largest in early September (Pl.
Testes of mature individuals are pale yellow and slightly oblong.
Fox (1952) found that testes of garter snakes (Thamnophis sirtalis and T.
Sexual Cycle of Males Testes were preserved in each month from April to October.
Size of testes was expressed as the average length (greatest diameter) of both testes.
But in the higher invertebrates and vertebrates there is a sex-differentiation among the individuals, the adult males being possessed of testes only and producing sperms, the adult females possessed of ovaries only and producing ova.
Not infrequently, as in the earthworm, each individual has both testes and ovaries, and thus produces both ova and sperms, but from different organs.
In these new colonies, again, the parts which are to become ovaries or testes float off, and ripen their products in free-swimming, medusoid organisms.
The ovaries or testes make their appearance at a very early period as ridges of the middle layer projecting into the body-cavity.
Finally, the testes are purely abdominal in some, and in none is there a full descent into a scrotum, as in the more highly-developed Eutheria.
The testesare extra-abdominal, but hang in front of the penis.
Thirdly, the testes are abdominal throughout life, a character which they share with such lowly-organised animals as the Monotremata and the Whales.
If the testes of a man are removed he will assume the characteristics of a woman.
There would seem to be no good reason to doubt that if the male organs of a young goat do rejuvenate the atrophied testes of a man, which Dr.
Brinkley's work up to the present having been confined to the transplantation of testes and ovaries.
Some unfortunate young male is deprived of his testesby Steinach, and these are implanted forthwith in this hoary old rat.
