Genital duct diaulic; male and female apertures contiguous.
Genital duct triaulic. Spicules present in the mantle.
Genital duct always triaulic, and male and female apertures distant from each other.
The portion of the lachrymal duct communicating with the cavity of the nose has, on the other hand, been abnormally developed, apparently for the purpose of cleansing that chamber from particles of sand which may obtain an entrance while the animal is burrowing.
In Lanice conchilega the posterior series of nephridia are connected by a thick longitudinal duct, which seems to be seen in its most reduced form in Owenia, where a duct on each side runs in the epidermis, being in parts a groove, and receives one short tubular nephridium only and occupies only one segment.
The latter opens e, Hermaphrodite duct into the common duct at the point k, (uterine portion).
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 female portion of the duct is more complex.
The Auronectae are peculiar deep-sea forms, little known except from Haeckel's descriptions, in which the large pneumatophore has a peculiar duct, termed the aurophore, placed on its lower side in the midst of a circle of swimming-bells.
Quite independent of these are certain large dorsally situate funnel-like folds of the coelomic epithelium, ciliated, but of which no duct has been discovered leading to the exterior.
In the former, the duct, leading from the ovarian sac, and swelling along its course into the spherical sac, the "spermatheca," is highly suggestive of the oviduct and receptaculum of the Eudrilidae.
The gonad has no accessory organs and except in Neri- tidae no duct, but discharges into the right kidney.
U, Duct of same.
Poison-gland present whose duct traverses the nerve-collar.
Ing by means of a longish duct into a, Genital pore.
Closed in a viscid secretion at the point where the albuminiparous gland opens into the duct intertwined with it; and on reaching the pcint where the spermathecal duct debouches they are impregnated by the spermatozoa which escape now from the spermatheca and meet the ova.
In all these cases we have a duct which has a usually wide, always intercellular, lumen, generally, if not always, ciliated, which opens directly into the coelom on the one hand and on to the exterior of the body on the other.
In Lumbricus the connexion is a little closer; the funnel of the nephridium, in the segments in which the funnels of the gonad ducts are to be developed, persists and is continuous with the gonad duct funnels on their first appearance.
This fact led Cuvier erroneously to the belief that a duct existed leading from the gonad to this papilla.
13), is, as in other Aspidobranchia, devoid of a special duct communicating with the exterior.
The genital duct is now trifurcated or triaulic, a condition which is confined to certain Nudibranchs, viz.
K, Opening of the albuphrodite duct, which very soon becomes miniparous gland into P Y the hermaphrodite entwined in the spire of a gland - the duct.
And here also is a small diverticulum of b, Vaginal portion of the the duct f.
Genital duct diaulic, without open seminal groove; male and female apertures contiguous.
Genital duct diaulic; male and female apertures contiguous.
Where these folds cease the common duct splits into two portions, a male and a female.
This paired organ consists of a string of cells which are perforated by a duct opening to the exterior and ending internally in a flame-cell.
The female genital opening usually lies in front of the eighth abdominal segment, the male duct opens on the ninth.
The median vagina, spermatheca and ejaculatory duct are, on the other hand, formed by ectodermal inpushings.
Palmen (1884) on these ducts have shown that in may-flies and in female earwigs the paired mesodermal ducts open directly to the exterior, while in male earwigs there is a single mesodermal duct, due either to the coalescence of the two or to the suppression of one.
The ejaculatory duct which opens on the ninth abdominal sternum in the adult male arises in the tenth abdominal embryonic segment and subsequently moves forward.
These posterior brain-lobes, which in all Heteronemertines are in direct continuity of tissue with the upper pair of principal lobes, cease to have this intimate connexion in the Metanemertini; and, although still constituted of (I) a ciliated duct, opening out externally, (2) nervous tissue surrounding it, and (3) histological elements distinctly different from the nervous, and most probably directly derived from the oesophageal outgrowths, they are nevertheless here no longer constantly situated behind the upper brain-lobes and directly connected with them, but are found sometimes behind, sometimes beside and sometimes before the brain-lobes.
A long cystic duct would point to a long reign of the king.
Bancrofti is known to live in the lymphatic glands, and its embryos Microfilaria sanguinis hominis nocturna, passing by the thoracic duct, reach the blood-vessels and circulate in the blood.
The orifice of invagination forms a pore which may be closed up or may form a protruding duct or funnel.
As regards the inner ear, the endolymphatic duct ends in a closed saccus, imbedded in the dura mater of the cranial cavity.
The more complete replacements, such as the nephridia of the genital segment of Tubifex by a subsequently formed genital duct, may be compared with the succession of the nesonephros to the pronephros in vertebrates, and of the metanephros to the mesonephros in the higher vertebrates..
From this vagina arises a narrow duct leading to the exterior.
A further degree of modification occurs when the male duct takes its origin from the hermaphrodite duct above the external opening, so that there are two distinct apertures, one male and one female, the latter being the original opening.
The genital duct is now said to be diaulic, as in Valvata, Oncidiopsis, Actaeon, and Lobiger among the Bullomorpha, in the Pleurobranchidae, in the Nudibranchia, except the Doridomorpha and most of the Elysiomorpha, and in the Pulmonata.
This second duct has normally no spermathecal gland at its termination, which is simple and blunt.
Male duct (vas deferens).
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.
In this duct and sac the spermatophores received in copulation from another snail are lodged.
In all these cases the female duct bears a bursa copulatrix or receptaculum seminis.
Soon after quitting the uterus it is joined by a long duct leading from a glandular sac, the spermatheca (Rf).
All spiders possess a pair of poison-glands, one in each of the chelicerae or mandibles and opening by means of a duct at the tip of the fang.
The upper, wide opening of the duct is attached by elastic, peritoneal lamellae to the hinder margin of the left lung; the middle portion of the duct is glandular and thick-walled, for the deposition of the albumen; it is connected by a short, constricted " isthmus " (where the shell-membrane is formed) with a dilated " uterus " in which the egg receives its calcareous shell and eventual pigmentation.