Though the paired arrangement of the nephridia is the prevalent one in the Chaetopoda, there are many examples, among the Oligochaeta, of species and genera in which there are several, even many, nephridia in each segment of the body, which may or may not be connected among themselves, but have in any case separate orifices on to the exterior.
In terrestrial A, Lumbricus : 9, to, segments contain ing spermathecae, the orifices of forms dorsal pores are usuwhich are indicated; 14, segment b ally present; in aquatic earing oviducal pores; 15, segforms a head pore only.
B Acanthodrilus: cp, orifices of sperminal, rarely dorsal, at a math ecae;, oviducal pores; little distance from end male pores; on 17th and 19th of body.
6, d), which were originally described by Lankester as orifices possibly connected with the evacuation of the generative products.
On account of their position they were termed by him the " capito-pedal orifices," being placed near the junction of head and foot.
The gonapophyses are the projections near the extremity of the body that surround the sexual orifices, and vary extremely according to the kind of insect.
The great dorsal contractile vessel or " heart " of Limulus is closely similar to that of Scorpio; its ostia or incurrent orifices are FIG.
Sci., Igor.) orifices of the lung-chambers of modern scorpions, can be found in the Scottish specimen of Palaeophonus, which presents the ventral surface of the animal to view.
The attention of Newton was also directed to the discharge of water from orifices in the bottom of vessels.
His object was to measure the contracted part of a fluid vein, to examine the phenomena attendant on additional tubes, and to investigate the form of the fluid vein and the results obtained when different forms of orifices are employed.
Extensive experiments on the discharge of water from orifices (Experiences hydrauliques, Paris, 1832) were conducted under the direction of the French government by J.
- Zooecia, long and coherent, prismatic or cylindrical, with terminal orifices, their wall thin and simple in structure proximally, thickened and complicated distally.
Orifices of the zooecia often separated by pores (mesopores).
The ovicells commonly found as globular swellings surmounting the orifices are not direct modifications of zooecia, and each typically contains a single egg or embryo.
In the encrusting type, which is found in a large proportion of the genera, the zooids are usually in a single layer, with their orifices facing away from the substratum; but in certain species the colony becomes multilaminar by the continued superposition of new zooids over the free surfaces of the older ones, whose orifices they naturally occlude.
The zoarium may rise up into erect growths composed of a single layer of zooids, the orifices of which are all on one surface, or of two layers of zooids placed back to back, with the orifices on both sides of the fronds or plates.
The platypus is aquatic in its habits, passing most of its time in the water or close to the margin of lakes and streams, swimming and diving with the greatest ease, and forming for the purpose of sleeping and breeding deep burrows in the banks, which generally have two orifices, one just above the water level, concealed among long grass and leaves, and the other below the surface.
Besides the four orifices through which water flowed into it there were two other holes about 4 in.
It stops over one of three orifices in the bottom plate of the balance.
- First segment of hind-body footless, bearing the orifices of the genital organs (in the male unsymmetrically placed); last foot of the fore-body in the male a copulatory organ; neither, or only one, of the first pair of antennae in the male geniculating; cephalic limbs abundantly articulated and provided with many plumose setae; heart generally present.
- The first segment of the hind-body almost always with rudimentary pair of feet; orifices of the genital organs (symmetrically placed in both sexes) in the following segment; neither the last foot of the fore-body nor the rudimentary feet just mentioned acting as a copulatory organ in the male; both or neither of the first pair of antennae in the male geniculating; cephalic limbs less abundantly articulated and with fewer plumose setae or none, but with hooks and clasping setae.
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.
And of two auricles which open into the ventricle by orifices protected by valves.
Cyrenidae.-Two siphons, more or less united, with papillose orifices; pallial line Inj 6 r 6.
Cycladidae.-One siphon or two free siphons with simple orifices; pallial line simple; hermaphrodite, embryos incubated in external gill-plate; freshwater, Cyclas; British.
- Siphons short and separate; branchial siphon with a large valve; branchial septum bears two groups of orifices on either side; hermaphrodite.
- Branchial septum with three groups of orifices on each side; siphons short, separate, branchial siphon with a valve.
- Branchial septum with four or five pairs of very narrow symmetrical orifices; siphons long, united, their extremities surrounded by tentacles; sexes separate.
The glands of Bartholin are two oval bodies about half an inch long, lying on each side of the vagina close to its opening; they represent Cowper's glands in the male, and their ducts open by minute orifices between the hymen and the labia minora.
The arteries and veins have proper endothelial walls; they pass abruptly into the sinuses and in some cases communication is effected by orifices in the walls of the vessels, as for example in the vena cava of Nautilus.
In the skull there are two orifices to the lachrymal duct, situated on or inside the rim of the orbit.
It is formed of pavement epithelial cells, mainly grouped in a concentric manner around the vascular papillae of the subcorneous integument, so that a section near the base of the hoof, cut transversely to the long axis of these papillae, shows a number of small circular or oval orifices, with cells arranged concentrically round them.
The stomach of the horse is simple in its external form, with a largely developed right cul de sac, and is a good deal curved on itself, so that the cardiac and pyloric orifices are brought near together.
2) shows: the mouth (m), continuous on either side with the groove between the two series of tentacles; the anus (a), in the middle line, at no great distance from the mouth; a transversely elongated epistome (ep), between the mouth and the anus; and, in the concavity of the lophophore, the apertures of the nephridia (n.o.) which, according to De Selys-Longchamps, open into the two large sensory or glandular "lophophoral organs " the orifices of which are seen at gl.
The Hexapoda are all provided with a highly developed tracheal system, which presents considerable variation in regard to its stigmata or orifices of communication with the exterior.
Tracheae are essentially tubes like bloodvessels - apparently formed from the same tissue elements as bloodvessels - which contain air in place of blood, and usually communicate by definite orifices, the tracheal stigmata, with the atmosphere.
Each zooid buds from the one immediately preceding it in the series, and intercommunication is effected by all the budding orifices (including that in the wall of the sicula) remaining permanently open.
But in striking contrast to what obtains among the Graptoloidea in general, the budding orifices in the Dendroidea become closed,, and all the various cells shut off from each other.
13 a the usual materials employed for lining the well and holding up the sand, and the quantity of water drawn is kept below the comparatively small quantity necessary to produce a velocity, through the joints or orifices, capable of disturbing the sand.
Of the cast-iron cylinders forming the well was provided with about 660 small orifices lined with gun-metal tubes or rings, each armed with numerous thicknesses of copper wire gauze, and temporarily closed with screwed plugs.
To remove this obstruction the water was pumped out while the plugs kept the orifices closed.
Many orifices through which water at first only dribbled were thus caused to discharge water with great force, and entirely free from sand, against the opposite side of the well, while the general result was to increase the inflow of water many times, and to entirely prevent the intrusion of sand.