The mesothoracic epimera bound the coxal cavities of the intermediate legs.
Body-cavities of zooids continuous with one another.
- This tribe is distinguished from the Malacoderma and allied groups by the mesothoracic epimera not bounding the coxal cavities of the intermediate legs.
These cavities communicate with the exterior through the gonad ducts, which have nothing to do with them, but whose coelomic funnels are taken up by them in the course of their growth.
In Hirudo and the Gnathobdellidae there is only one system of cavities which consist of four principal longitudinal trunks, of which the two lateral are contractile, which communicate with a network ramifying everywhere, even among the cells of the epidermis.
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.
The cells which line them and also the cavities of the tubes contain urates, which are excreted from the blood in the surrounding bodycavity.
It is therefore a haemocoel, the coelom of the developed insect being represented only by the cavities of the genital glands and their ducts.
The feelers are very small and are often hidden in cavities beneath the head.
There are five pairs of larger sacs belonging to the pulmonary system: - (1) prebronchial or cervical, extending sometimes far up the neck, even into the cranial cavities; the throat-bags of the prairie fowls (Cupidonia and Pedioecetes) are a further development; (2) subbronchial or interclavicular; (3 and 4) anterior and posterior thoracic or intermediate; (5) abdominal sacs.
Such crystals occur either in cavities in mineral-veins and in granitic rocks, or as a lining in agate geodes.
Much fine amethyst comes from Russia, especially from near Mursinka in the Ekaterinburg district, where it occurs in drusy cavities in granitic rocks.
Free sulphur may also result from the decomposition of pyrites, as in pyritic shales and lignites, or from the alteration of galena: thus crystals of sulphur occur, with anglesite, in cavities in galena at Monteponi near Iglesias in Sardinia; whilst the pyrites of Rio Tinto in Spain sometimes yield sulphur on weathering.
The successive cavities are not, however, completely closed from each other; there is some communication between adjoining segments, and the septa are sometimes deficient here and there.
Crystals are found as a rarity in the amygdaloidal cavities of igneous rocks.
Such a rock is typically exemplified by a coarse-grained sandstone or conglomerate, while a limestone may be naturally porous, or, like the Trenton limestone of Ohio and Indiana, rendered so by its conversion into dolomite and the consequent production of cavities due to shrinkage - a change occurring only in the purer limestones.
As the ova are in many species deposited in a gelatinous tube secreted by the bodywalls, in which they are arranged (three or more together) in flaskshaped cavities, impregnation must probably take place either before or at the very moment of their being deposited.
The adult stage, for example, has been found in the nasal passages of sheep, goats, horses and even of man, and the larval stage in the pleural and peritoneal cavities of dogs and cats.
In the adult of both sexes there are only two teeth, both in the upper jaw, which lie horizontally side by side, and in the female remain throughout life concealed in cavities of the bone.
Pectolite is a secondary mineral occurring as white masses with a radially fibrous structure in the veins and cavities of basic igneous rocks.
Sometimes the central canal is wide and uninterrupted between the two neuropores; in other cases it becomes broken up into a large number of small closed medullary cavities, and in others again it is obsolete.
The coagulum is next flattened out by a wooden or iron roller to get rid of the cavities containing watery liquid, and the sheets are then hung up for fourteen days to dry, when they weigh about 2 lb, the sheets being usually z to a in.
The best crystallized specimens of any mica are afforded by the small brilliant crystals of biotite, which encrust cavities in the limestone blocks ejected from Monte Somma, Vesuvius.
These sinuses are completely shut off from all other cavities, they do not open into the main coelomic space nor into the small arm-sinus, nor does the right sinus communicate with the left.
Of these latter, two grades were further distinguished by Lankester - those which remain possessed of a single archenteric cavity and of two primary cell-layers (the Coelentera or Diploblastica), and those which by nipping off the archenteron give rise to two cavities, the coelom or body-cavity and the metenteron or gut (Coelomata or Triploblastica).
Dropsy During conditions of health a certain quantity of lymphy liquid is constantly being effused into the tissues and serous cavities of the body, but in the case of the tissues it never accumulates to excess, and in that of the serous cavities it is never more than sufficient to keep them moist.
Where the dropsical condition is more or less general the term " anasarca " is applied to it; if the tissues are infiltrated locally the term " oedema " is employed; and various names are applied, with a local significance, to dropsies of individual parts or cavities, such as " hydrothorax," " hydroperitoneum " or " ascites," " hydrocephalus," and so on.
Dropsy of the serous cavities is very commonly merely part of a general anasarca, although occasionally it may be, as in the case of ascites, the sequel to an obstruction in the venous return.
Skin-grafting and regeneration of bone are among not the least remarkable applications of pathological principles to the combat with disease in recent times; and in this connexion may also be mentioned the daring acts of surgery for the relief of tumours of the brain, rendered practicable by improved methods of localization.
Thus the defects, whether of this secretion or of that, and again of motor activity, the state of the valvular junctions, the volume of the cavities, and their position in the abdomen, may be ascertained, and dealt with as far as may be; so that, although the fluctuations of chemical digestion are still very obscure, the application of remedies after a mere traditional routine is no longer excusable.
They are usually found in the alimentary canal or its appendages but occasionally work their way into the serous cavities, nervous system and blood vessels.
It has a pharynx and short straight digestive sac: and its mesenchymatous cavities are filled with germ-balls in various stages of development.
Body-cavities of zooids not continuous with one another.
The cavities of the hollow tentacles open into a circular canal which surrounds the oesophagus at the base of the lophophore.
Accidents are rarely caused by them, because they are extremely shy and swim away on the least alarm; but, when surprised in the submarine cavities forming their natural retreats, they will, like any other poisonous terrestrial snake, dart at the disturbing object; and, when out of the water, they attempt to bite every object near them, even turning round to wound their own bodies.
Journ., 1828), he devoted himself chiefly to the examination of fluid-filled cavities in crystals, and of the microscopic structure of various kinds of fossil wood.
Then followed the discovery of " hard rockphosphate," a massive mineral, often having cavities lined with nearly pure phosphorite.
(2) The body contains but a single internal cavity, the coelenteron or gastrovascular space, which may be greatly ramified, but is not shut off into cavities distinct from the central digestive space.
Shaler, state geologist in 1873-1880, " When the rocks whence they flow were formed on the Silurian sea-floors, a good deal of the sea-water was imprisoned in the strata, between the grains of sand or mud and in the cavities of the shells that make up a large part of these rocks.
In the Upper Mississippi lead region of Missouri, Illinois, Iowa and Wisconsin the ore fills large cavities or chambers in limestone.
Fred O'Connor banged into the room with a look-ma-no-cavities smile on his face.
Fleas are wingless insects, with a laterally compressed body, small and indistinctly separated head, and short thick antennae situated in cavities somewhat behind and above the simple eyes, which are always minute and sometimes absent.
Glessite, a nearly opaque brown resin, with numerous microscopic cavities and dusty enclosures, named from glesum, an old name for amber.
Of the cell-wall (which is secreted by the living cell-body) the protoplasm dies, and a tissue in which this has occurred consists solely of the dead framework of cell-walls, enclosing in the cavities, originally occupied by the protoplasm, simply water or air.
These cavities are completely roofed by a layer of cells; in the centre of the roof is a pore surrounded by a ring of special cells.
In a few cases some of the tracheids have very thick walls and reduced cavities, functioning as mechanical rather than as waterconducting elements.
Coprolites have been found at Lyme Regis, enclosed by the ribs of ichthyosauri, and in the remains of several species of fish; also in the abdominal cavities of a species of fossil fish, Macropoma Mantelli, from the chalk of Lewes.
Ann, Chitinous annulus, containing air cavities which enable the stato blast to float.
The book was the Gospel, and the white thing with the lamp inside was a human skull with its cavities and teeth.
The ovary has many cavities with a large number of ovules attached to its walls, and is surmounted by a flat stigma of many radiating rows as in a poppy.
Thus the disposition of the endoderm-cavities is roughly comparable to the gastrovascular system of a medusa.
The epithem is penetrated by a network of fine intercellular spaces, which are normally filled with water and debouch on one or more intercellular cavities below the epidermis.
The same happenchance brought us the learning that children in schools with fluorescent lights get fewer cavities than those in schools with incandescent lighting.
Frost blisters are pustular swellings due to the up-growth of callus-tissue into cavities caused by the uprising of the superficial cortex under the action of intense cold.
The other is that the vessels are not empty, but that the water travels in their cavities, which contain columns of water in the course of which are large bubbles of air.