The body-cavity is largely occupied by processes from the large muscle cells of the skin.
These processes stretch across the body cavity to be inserted in the dorsal and ventral middle lines.
It is evident that the outer envelope of the gonophore represents the ex-umbral ectoderm (ex.), and that the inner ectoderm lining the cavity represents the sub-umbral ectoderm of the free medusa.
It is seen from the foregoing account of medusa - budding that the entocodon is a very important constituent of the bud, furnishing some of the most essential portions of the medusa; its cavity becomes the subumbral cavity, and its lining furnishes the ectodermal epithelium of the manubrium and of the sub-umbral cavity as far as the edge of the velum.
The future D, E); the cavity A between the two B C walls of the cup FIG.
` tion of the coelenteric 1 V cavity; in the second stage the tentacles Much modified from C. Chun, " Coelenterata," in grow out as secondary Bronn's Tierreich.
The sub-umbral cavity (s.c.) functions as a brood-space for the developing embryos, which are set free by rupture of the wall.
The body-cavity also contains the socalled phagocytic organs.
St.c, Cavity of statocyst.
S, Optical section of part of thick-walled stereid of Phanerogam, with almost obliterated cavity and narrow slit-like oblique pits.
The scene in the next room – an open cavity filled with rusted equipment – baffled her.
In correspondence with the fundamental constitution of the zooid, each of the three segments has its own body-cavity separated from the others.
Silver, sufficient to fill loosely about half the cavity between the plugs, which fit tightly into the tube.'
St.c, Cavity of statocyst.
The next step is the gradual obliteration of the sub-umbral cavity by disappearance of which the sub-umbral ectoderm comes into contact with the ectoderm of the manubrium.
The endodermal spadix (sp) of the sporosac represents the endoderm of the manubrium; the ectodermal lining of the sporosac (ex.) represents the ex-umbral ectoderm of the medusa; and the intervening layers, together with the sub-umbral cavity, have disappeared.
45, C, ed.) may be formed over all, as in Garveia, &c.; or the entocodon may remain solid and without cavity until after the formation of the manubrium, or may never acquire a cavity at all, as described above for the gonophores.
The entocodon, however developed, gives rise at first to a closed cavity, representing a closing over of the umbrella, temporary in the bud destined to be a free medusa, but usually permanent in the sessile gonophore.
In such cases the characters of the adult tissue clearly depend solely upon the characters of the cell-walls, and it is usual in plant-anatomy to speak of the wall with its enclosed cavity as the cell, and the contained protoplasm or other substances, if present, as cell-contents.
The cells of the staminal hairs of Tradescantia air ginica contain a large sap-cavity across which run, in.
A membranous, or ossified, tube which rises from a pneumatic foramen in the os articulare, on the median side of the articulation, and passes upwards between the quadrate and lateral occipital bone, opening into the cavity of the middle ear.
From the shape and position of the phagocytic organs it is obvious that they form admirable strainers through which the fluid of the body-cavity filters (figs.
The worm inhabits the lung of the frog and toad, and is hermaphrodite (Schneider) or parthenogenetic (Leuckart); the embryos hatched from the eggs find their way through the lungs into the alimentary canal and thence to the exterior; in a few days they develop into a sexual larva, called a Rhabditiform larva, in which the sexes are distinct; the eggs remain within the uterus, and the young when hatched break through its walls and live free in the perivisceral cavity of the mother, devouring the organs of the body until only the outer cuticle is left; this eventually breaks and sets free the young, which are without teeth, and have therefore lost the typical Rhabditis form.
5) was attached a diaphragm D of thin sheet iron; in front of this was a cover M, M provided with a suitable cavity for directing the sound-waves against the diaphragm.
The cavity of the pitcher is in some species lined throughout with a smooth glistening surface over which glands are uniformly distributed; these glands secrete a liquid which is found in the pitcher even in the young state while it is still hermetically closed by the lid.
Other species the glands are confined to the lower portion of the cavity surface, while the upper part bear a smooth waxy secretion on which it is impossible, or at any rate extremely difficult, for insects to secure a foothold.
Downwards and meet in the centre of the diminishing cavity so as to render escape impossible.
The coenosarc constitutes a system by which the digestive cavity of any one polyp is put into communication with that of any other individual either of the trophosome or gonosome.
S.c, Cavity of ento- v, Velum.
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.
By a simple modification, the open pit becomes a solid ectodermal ingrowth, just as in Teleostean fishes the hollow medullary tube, or the auditory pit of other vertebrate embryos, is formed at first as a solid cord of cells, which acquires a cavity secondarily.
When the bud is nearly complete, the body-wall of the parent immediately below it becomes perforated, placing the coelenteric cavity of the parent in secondary communication with that of the bud (H), doubtless for the better nutrition of the latter.
Endoderm, containing the st, Stomach, which in H ac coelenteric cavity (cod), quires a secondary com while the outer layer munication with the diges furnishes the future ectotive cavity of the mother.
The parasitic actinula is found attached to the proboscis of the medusa; it thrusts its greatly elongated hypostome into the mouth of the medusa and nourishes itself upon the food in the digestive cavity of its host.
Hence the cavity of the air-sack is equivalent to a sub-umbral cavity in which no manubrium is formed, and the pore or orifice of invagination would represent the margin of the umbrella.
In other types the medusae may be set G, Cavity of the large central and a " trachea.
The endoderm of the planula now acquires a cavity, and at the narrower pole a mouth is formed, giving rise to the primary siphon.
In most cases the organic structure has disappeared, le i tving only a cavity, with perhaps a trace of chitin.
The whole cavity of the cell is sometimes stuffed with proteid contents.
Above each cavity is situated a so-called water-sloma, no doubt derived phylogenetically from an ordinary stoma, and enclosed by guard-cells which have nearly or entirely lost the power of movement.
A ventral vessel occurs on the anterior side of the metasome and forms a loop extending down the entire length of the stalk, while a " heart " projects into the cavity of the pericardium, probably connected on the ventral side of the notochord with the ventral vessel, and on its dorsal side with the dorsal vessel.
Except that in each sex the b.c 3 ., Body cavity of metasome.
The tympanic process of the alisphenoid bone of the skull is short, not covering the cavity of the tympanum, nor reaching the paroccipital process.
St.c, Cavity of statocyst.
St.c, Cavity of statocyst.
Ea c h cordylus is a tentacle-like structure with an endodermal axis containing an axial cavity which may be continuous with the ring-canal, or may be partially occluded.
40); in Geryonia, however, it remains double, and the centripetal canals arise by parting of the two layers; (4) excretory endoderm, lining pores at the margin of the umbrella, occurring in certain Leptomedusae as socalled " marginal tubercles," opening, on the one hand, into the ring-canal and, on the other hand, to the exterior by " marginal funnels," which debouch into the sub-umbral cavity above the velum.
44, E), and at the same time the base of the cup is thrust upwards to form the manubrium (m), converting the cavity of the entocodon into a space which is crescentic or horse-shoe-like in section.
The naked cells which have been alluded to live in water, and call therefore for no differentiation in connection with this necessity; but those which are surrounded by a cell-wall always develop within themselves a vacuole or cavity which occupies the greater part of their interior, and the hydrostatic pressure of whose contents keeps tha protoplasm in contact with the membrane, setting up a condition of turgidity.
D, Nuclear cavity with chromosomes.
It was a small cavity under ten feet of water; but I think that I can warrant the pond not to need soldering till they find a worse leak than that.