noun
definition
An elongated tube from the head or connected to the mouth, of an animal.
definition
(mildly) A large or lengthy human nose.
Examples of proboscis in a Sentence
A proboscis absent, but jaws usually present.
The proboscis bears at its extremity a circlet of smaller oral tentacles.
To reach the honey in the spur of the flower, the insect must thrust its proboscis into the flower close under the globular head of the stigma.
The stomach may be drawn out into the manubrium, forming a proboscis (" Magenstiel ") of considerable length.
Shell turriculated and siphonated, thick, each whorl with varices; foot broad and truncated anteriorly; pallial siphon well developed; proboscis present.
The sucker-bearing processes of Pneumonoderma are outgrowths of the proboscis.
Mandibles rarely present, adapted for piercing; first maxillae with palps; second maxillae forming with hypopharynx a suctorial proboscis.
Biting mandibles; second maxillae incompletely or completely fused; often forming a suctorial proboscis.
On the other hand, they are much less considerably or even insignificantly so in the genera that are known to make a rather sparing use of their proboscis.
The rhynchocoel is formed by a split which appears in the mesoblast surrounding the epiblastic pit which is the forerunner of the proboscis.
In addition to the musculature of the proboscis and proboscidian sheath, longitudinal muscular fibres are found in the walls of the oesophagus, whilst transverse ones are numerous and united into vertical dissepiments between the successive intestinal caeca, thus bringing about a very regular internal metamerization.
This is brought about by a double commissure, of which the ventral portion is considerably thicker than the dorsal, and which, together with the brain-lobes, constitutes a ring through which both proboscis and proboscidian sheath pass.
Two lateral, shallow pits occur on the side of the body about the level of the hinder end of the proboscis in some species of the genus Carinella, which are termed side-organs.
As to the organ of touch, the great sensitiveness of the body has already been noticed, as well as the probable primary significance of the proboscis.
The proboscis is an invagination from the epiblast; the proboscidian sheath appears in the mesoblast, but is perhaps originally derived from the hypoblast.
B, The proboscis of one still more highly magnified.
The body is divisible into a proboscis and a trunk with sometimes an intervening neck region.
The proboscis bears rings of recurved hooks arranged in horizontal rows, and it is by means of these hooks that the animal attaches itself to the tissues of its host.
Like the body, the proboscis is hollow, and its cavity is separated from the body cavity by a septum or proboscis sheath.
Traversing the cavity of the proboscis are muscle-strands inserted into the tip of the proboscis at one end and into the septum at the other.
Except for the absence of 'the longitudinal fibres the skin of the proboscis resembles that of the body, but the fluid-containing tubules of the latter are shut off from those of the body.
The canals of the proboscis open ultimately into a circular vessel which runs round its base.
Each consists of a prolongation of the syncytial material of the proboscis skin, penetrated by canals and sheathed with a scanty muscular coat.
They seem to act as reservoirs into which the fluid of the tense, extended proboscis can withdraw when it is retracted, and from which the fluid can be driven out when it is wished to expand the proboscis.
A, The larva of Echinorhynchus proteus from the body cavity of Phoxinus laevis, with the proboscis retracted and the whole still enclosed in a capsule.
B, A section through the same; a, the invaginated proboscis; b, proboscis sheath; c, beginning of the neck; d, lemniscus.
Nose and upper lip elongated into a flexible, mobile snout or short proboscis, near the end of which the nostrils are situated.
The name has reference to the tongue-shaped muscular proboscis by which the animal works its way through the sand.
The proboscis is not the only organ of locomotion, being assisted by the succeeding segment of the body, the buccal segment or collar.
By the waves of contraction executed by the proboscis accompanied by inflation of the collar, progression is effected, sometimes with marvellous rapidity.
In accordance with this manner of feeding, the mouth is kept permanently open and prevented from collapsing by a pair of skeletal cornua belonging to a sustentacular apparatus (the nuchal skeleton), the body of which lies within the narrow neck of the proboscis; the latter is inserted into the collar and surrounded by the anterior free flap of this segment of the body.
The proboscis-pores are highly variable, and frequently only one is present, that on the left side; sometimes the pore-canals of the proboscis unite to open by a common median orifice, and sometimes their communication with the probosciscoelom appears to be occluded, and finally the pore-canals may be quite vestigial.
The proboscis-gut occurs as an outgrowth from the anterior dorsal wall of the collar-gut, and extends forward into the basal (posterior) region of the proboscis, through the neck into the proboscis-coelom, ending blindly in front.
In the neck of the proboscis the fibrous layer is greatly thickened, and other intensifications of this layer occur in the dorsal and ventral middle lines of the trunk extending to the posterior end of the body.
The anthers shed their pollen into this groove, either of themselves or when the pistil is shaken by the insertion of the bee's proboscis.
The proboscis, passing down this groove to the spur, becomes dusted with pollen; as it is drawn back, it presses up the lip-like valve of the stigma so that no pollen can enter the stigmatic chamber; but as it enters the next flower it leaves some pollen on the upper surface of the valve, and thus cross-fertilization is effected.
Proboscis free, not supported from below by either the prosternum or the basal segments of the appendages of the 2nd pair.
Appendages of 2nd pair very large and completely chelate, their basal segments meeting in the middle line, as in the Uropygi, and provided in front with membranous lip-like processes underlying the proboscis.
The projecting feature above the mouth, to which the word is usually restricted in man, is, in the case of the lower animals, called snout or muzzle, or, if much prolonged, proboscis or trunk.
C, portion of a proboscis showing the two forms of hooks; highly magnified.
The palpi vary in form and in the number of their component segments, and the proboscis, though usually straight, may be curved (as in Megarhinus) or otherwise modified in shape.
The Anophelinae have narrow bodies, and generally spotted wings, and when at rest keep body and proboscis in a straight line, often at a considerable angle with the supporting surface; in this way they can be distinguished from Culicinae, which have a humped-up thorax with which the proboscis forms an angle, and in the resting position keep the body parallel to the support.
The former is specially modified in a few genera in a manner analogous to the "proboscis" of certain Rhabdocoel Turbellaria.
In appearance tsetse are somewhat narrow-bodied flies, with a prominent proboscis, which projects horizontally in front of the head, and with the wings in the resting position closed flat one over the other like the blades of a pair of scissors.
In all tsetse-flies the proboscis in the living insect is entirely concealed by the palpi, which are grooved in their inner sides and form a closely fitting sheath for the piercing organ; the base of the proboscis is expanded beneath into a large onion-shaped bulb, which is filled with muscles.
The head of the insect contains a muscular pharynx by means of which the blood from the wound inflicted by the proboscis (labium) is pumped into the alimentary canal and the so-called sucking-stomach.
The tip of the proboscis is armed with a complicated series of chitinous teeth and rasps, by means of which the fly is enabled to pierce the skin of its victim; as usual in Diptera the organ is closed on the upper side by the labrum, or upper lip, and contains the hypopharynx or common outlet of the paired salivary glands, which are situated in the abdomen.
The proboscis of tsetse-flies is without the paired piercing stilets (mandibles and maxillae) possessed by other bloodsucking Diptera, such as the female horse-flies and mosquitoes.
The act of feeding, in which the proboscis is buried in the skin of the victim nearly up to the bulb, is remarkably quick, and in thirty seconds or less the abdomen of the fly, previously flat, becomes swollen out with blood like a berry.
Enderlein has recently shown that the jaws of the Hemiptera can be recognized in a reduced condition in connexion with the louse's proboscis, the modification is so excessive that the group certainly deserves ordinal separation.