Velum sentence example
Here the medusoid, attached by the centre of its ex-umbral surface, has lost its velum and sub-umbral muscles, its sense organs and mouth, though still retaining rudimentary tentacles.
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 manubrium bearing the gonads is mouthless, and the umbrella is without tentacles, sense-organs, velum or radial canals.
The communication with the atrium is guarded by a valvula cardiaca dextra, which only in function represents the mammalian tricuspid; it consists of an oblique reduplication of the muscular fibres together with the endocardiac lining of the right ventricle, while the opposite wall is convex and forms neither a velum nor papillary muscles, nor chordae tendineae.
The preconchylian invagination or shell-gland is formed in the embryo behind the velum, on the surface opposite the blastopore.Advertisement
In forms which are naked in the adult state, the shell falls off soon after the reduction of the velum, but in Cenia, Runcina and Vaginula the shell-gland and shell are not developed, and the young animal when hatched has already the naked form of the adult.
Foot divided into two, posterior half bearing the operculum; a wide epipodial velum; shell turbinated.
Head broad, surrounded by a funnel-shaped velum or hood; no radula; dorsal appendages foliaceous.
There is a veliger stage in development, but the velum is reduced.
The larva for a time swims freely in the sea-water, having a circlet of cilia round the body in front of the mouth, forming the velum.Advertisement
The shell is developed on the dorsal surface behind the velum, the foot on the opposite or ventral surface behind the mouth.
The exumbral nerve-ring is the larger and supplies the tentacles; the subumbral ring supplies the velum.
The test is really a ciliated velum developed in the normal position at the apical pole but reflected backwards in such a way as to cover the original ectoderm except at the posterior end.
A similar modification of the velum occurs in Dentalium and in Myzomenia among the Amphineura.
It is termed the " velum," and is frequently drawn out (From Balfour, after Bobretzky.) FIG.Advertisement
There is a single pair of these organs situated immediately behind the velum.
Later the ciliated ring or velum disappears and seven imbricated calcareous plates, made up of flattened spicules, are formed on the dorsal surface.
The mouth consists of two portions, an outer vestibule and an inner apertura oris; the latter is surrounded by a sphincter muscle, which forms the so-called velum.
The velum is also provided with a circlet of twelve tantacles (in some species sixteen) which hang backwards into the pharynx; these are the velar tentacles.
The medusoids have a muscular velum of ectoderm and mesogloea only.Advertisement
The medusoids have no true velum; in some cases a structure more or less resembling this organ, termed a velarium, is present, permeated by endodermal canals.
The umbrella has a lobed, indented margin, a character only seen amongst Hydromedusae in the order Narcomedusae, and it is without the characteristic velum of the Hydromedusae; hence the Scyphomedusae are sometimes termed Hydrozoa Acraspeda.
A true velum, such as is found in Hydromedusae, never contains endoderm.
The velum is peculiar, being reflected backwards over the body and bearing, besides an apical tuft, three or four rings of cilia.
The foot arises as a prominence on the ventral surface and grows forward, and at the end of five or six days the velum atrophies and the foot becomes the organ of locomotion; the animal then ceases to swim and sinks to the bottom.Advertisement
The Rotifera are characterized by the retention of what appears in Molluscs and Chaetopods as an embryonic organ, the velum or ciliated prae-oral girdle, as a locomotor and foodseizing apparatus, and by the reduction of the muscular parapodia to a rudimentary or non-existent condition in all present surviving forms except Pedalion.
The palate is long and narrow; its mucous surface has seventeen pairs of not very sharply defined oblique ridges, extending as far back as the last molar tooth, beyond which the velum palati extends for about 3 in., having a soft corrugated surface, and ending posteriorly in an arched border without a uvula.
Under ordinary circumstances the horse breathes entirely by the nasal passages, the communication between the larynx and the mouth being closed by the velum palati.
The range over which the velum opens depends on when the previous obstruent was, and whether it was nasal.
Non-nasal-CNS | nasal-CNS The velum starts opening 20ms before the start of the nasal, finishes 10ms after the start of the nasal.
The tentacles are based on a muscular band called the velum.
The other, the " lower " or subumbral nerve-ring, is derived from the ectoderm on the sub-umbral side of the velum; it contains fewer but larger ganglion-cells and innervates the muscles of the velum (see diagram in article Medusae).
The pit has its opening turned towards the sub-umbral cavity, while it base or fundus forms a bulge, more or less pronounced, on the ex-umbral side of the velum.
B, Trochosphere of an Opisthobranch (Pleurobranchidium) showing - shgr, the shell-gland or primitive shell-sac; v, the cilia of the velum; ph, the commencing stomodaeum or oral invagination; ot, the left otocyst; pg, red-coloured pigment spot.
Velar articulation - we do this with the back of the tongue against the velum.
Closing the velum The velum is always fully open at the end of a nasal CNS.
Opening the velum The velum is always fully open at the end of a nasal CNS.
Beyond that, construction paper, velum, parchment, even transparent sheets will work.
These monogrammed velum paper cones hold soft petals for tossing at the bride and groom as they depart.
If you're looking for a retro style luggage set with just a touch of pink, Rupert Sanderson's unique cream velum retro luggage might be what you're looking for.
The sub-umbrella invariably shows a velum as an inwardly projecting ridge or rim at its margin, within the circle .of tentacles; hence the medusae of this sub-class are termed craspedote.
The muscle-fibres arise as processes from the bases of the epithelial cells; such cells may individually become sub-epithelial in position, as in the polyp; or, in places where muscular tissue is greatly developed, as in the velum or sub-umbrella, the entire muscular epithelium may be thrown into folds in order to increase its surface, so that a deeper sub-epithelial muscular layer becomes separated completely from a more superficial bodyepithelium.
The circular system is developed continuously over the entire subumbral surface, and the velum represents a special local development of this system, at a region where it is able to act at the greatest mechanical advantage in producing the contractions of the umbrella by which the animal progresses.
The nervous system of the medusa consists of sub-epithelial ganglion-cells, which form, in the first place, a diffuse plexus of nervous tissue, as in the polyp, but developed chiefly on the subumbral surface; and which are concentrated, in the second place, to form a definite central nervous system, never found in the polyp. In Hydromedusae the central nervous system forms two concentric nerverings at the margin of the umbrella, near the base of the velum.
One, the " upper " or ex-umbral nervering, is derived from the ectoderm on the ex-umbral side of the velum; it is the larger of the two rings, containing more numerous but smaller ganglioncells, and innervates the tentacles.