In C. nigrescens and in some other species a zooid may contain a pair of ovaries, a pair of testes, or an ovary and a testis, although the males, females and hermaj phrodites do not differ from one another in external characters.
There are three pairs of spermathecae situated in segments III-V, a testis in V and an ovary in VI.
Each testis communicates by means of an efferent duct with a common collecting duct of its side of the body, which opens on to the exterior by means of a protrusible penis, and to which is sometimes appended a seminal vesicle.
Here it lies close upon the genital body (ovary or testis), and in such intimate relationship with it that, when ripe, the gonad bursts into the renal sac, and its products are carried to the exterior by the papilla on the right side of the anus is FIG.
The testis t occupies a median position in the coiled visceral mass.
39) to the penis, and is by the aid of that eversible muscular organ introduced into the genital pore of a second Aplysia, whence it passes into the spermatheca, there to await the activity of the female element of the ovo-testis of this second Aplysia.
From the ovo-testis, which lies near the apex of the visceral coil, a common hermaphrodite duct ve proceeds, which receives the duct of the compact white albuminiparous gland, Ed, and then becomes much enlarged, the additional width being due to the development of glandular folds, which are regarded as forming a uterus u.
The male duct vd becomes fleshy and muscular near its termination at the genital pore, forming the penis p. Attached to it is a diverticulum fl, in which the spermatozoa which have descended from the ovo-testis are stored and modelled into sperm ropes or spermatophores.
Tubes, those of each testis opening into a vas deferens.
In the male of Phyllodromia the rudiment of a vestigial ovary becomes separated from the developing testis, indicating perhaps an originally hermaphrodite condition.
The testis is single, and its duct opens with the anus, and is provided with a couple of spicules.
Benham, " Testis of Limulus," Trans.
B, anterior portion more highly magnified (from Marshall and Hurst, after Sommer); cs, cirrus sac; d, ductus ejaculatorius; f, female aperture; o, ovary; od, oviduct; p, penis; s, shell-gland; t, anterior testis; u, uterus; va, vp, vasa deferentia; us, vesicula seminalis; y, yolk-gland; yd, its duct.
(Xioo.) reproductive system; C, Cirrus; H, hooks on the ventral sucker; I, small piece of the intestine to show its connexion with the reproductive organs by the narrow duct that passes from it to the union of the vaginae; M, mouth; 0, ovary; S, oral sucker; SC, sucker; SH, shell-gland; T, Testis; U, uterus; V, vaginal pore; Y, yolkgland.
The testis is a single compact organ.
The ovary (o) and the testis (t) of Ectoprocta are developed on the body-wall, on the stomach, or on the funiculus.
The male organs are usually a testis, a large seminal bladder and a protrusible penis.
The left inner gill-plate is also snipped to show the subjacent orifices of the left renal organ x, and of the genital gland (testis or ovary) y.
These forms are hermaphrodite, with an ovary and testis completely separate from each other on each side of the body, each having its own duct and aperture.
About the fifth week of human embryonic life the tunica albuginea appears in the male, from which septa grow to divide the testis into lobules, while the epithelial cords form the seminiferous tubes, though these do not gain a lumen until just before puberty.
From the adjacent mesonephros cords of cells grow into the attached part of the genital ridge, or testis, as it now is, and from these the rete testis is developed.
Recent research, however, points to these cords of the rete testis et ovarii as being derived from the coelomic epithelium instead of from the mesonephros.
In the male, as has been shown, it may form the rete testis, and certainly forms the vasa efferentia and globus major of the epididymis: in addition to these, some of its separate tubes probably account for the vas aberrans and the organ of Giraldes (see fig.
As the vas deferens approaches the prostate it enlarges and becomes slightly sacculated to act as a reservoir for the secretion of the testis; this part is the ampulla (see fig.
The sexes are distinct, and the ovary is frequently greenish in colour, the testis red.
Thorpe (London, 1848-1849); William of Malmesbury, De testis Pontificum Anglorum, edited by N.