There is, in birds, no annulus tympanicus.
a, the annulus, or remnant of C, longitudinal section of mature velum partiale.
The expression for w in (i) § 29 may be increased by the addition of the term im log z =-m0 + im log r, (1) representing vortex motion circulating round the annulus of liquid.
ann, Chitinous annulus, containing air cavities which enable the stato blast to float.
The sporangia dehisce by a transverse slit, the annulus being truly vertical or, in some of the genera in which they are regularly arranged, very slightly oblique.
These constellations were arranged in three concentric annuli, the northern ones in an inner annulus subdivided into 60 degrees, the zodiacal ones into a medial annulus of 1 zo degrees, and the southern ones into an outer annulus of 240 degrees.
The annuli into which segments are externally divided are so deeply incised as to render it impossible to distinguish, as can be readily done in the Oligochaeta as a rule, the limits of an annulus from that of a true segment.
cap. 3) - " Nullus hiatus est, nulla fractio, nulla dispersio formarum, invicem connexa sunt velut annulus annulo "; but it is almost clear that he was thinking only of a chain.
The figure Abdc is a sector of an annulus, which is the portion of a circle left after cutting out a concentric circle.
By unrolling each such element (§ 30) into a sector of a circular annulus, it will be found that the total area of the surface is M'.
The sporangium is of considerable size, and dehisces by a median slit, the annulus being a more or less definitely limited horizontal ring of cells near the apex.
The differences in the form and mode of dehiscence of the sporangia (those of the Simplices having median dehiscence and a horizontal annulus, those of the Gradatae a more or less oblique position of the annulus and of the plane of dehiscence, while in the Mixtae the annulus is vertical and the dehiscence transverse) stand in relation to the position of the sporangia in the sorus relatively to one another.
The absence of an annulus from their indehiscent sporangia makes it impossible to compare them with the other Ferns in respect of this important character.
a, Vascular bundle; c, hairs; b, d, annulus, magnified.
Each sporangium had, on one side only, a longitudinal or slightly oblique annulus, several cells in width; the numerous spores were all of the same size; certain differences among them, which have been interpreted as indicating heterospory, have now proved to depend merely on the state of preservation.
The latter is thick and short, and the wall of the sporangium, which opens by a median slit, has a group of thick-walled cells at the summit, forming the annulus.
annulus of each disk.
In the experimental part of this thesis, a novel method of visualizing flow in a rotating two-layer annulus is implemented.
The figure below shows the condenser annulus (left) and the phase plate (right) from a more appropriate angle.
This distinction was abandoned in May 1920 and thereafter all ball rounds had the purple annulus.
An outer annulus around this, is required to secure the ring but this may be ringed with the same paint.
In addition the following injuries can occur:- Cervical Disk Prolapse - caused by a rupture of the posterior disk annulus.
annulus fibrosis) surrounding a jelly-like cent r e (nucleus pulposus ).
annulus geometry: design for rising line, constant mean diameter, falling line.
annulus flow leads to increased vortex strength within the cavity.
While DF and COL offer at least the same resolution, phase contrast limits the resolution due to the condenser annulus.
Thus an INNER radius of 1 means that the sky annulus starts where the object aperture ends.
annulus>Wider apertured annuli are useful but do not seem to provide the subtle effects so easily.
Sometimes the annulus of the disk is completely torn and nuclear material escapes into the spinal canal.
lacrimal probe which can be inserted without damaging the annulus is used.
nucleus pulposus is the light colored area within the annulus fibrosus.
The section of a solid of revolution by a plane at right angles to the axis is an annulus or a sector of an annulus (fig.
" Concentric circles " are, as the name obviously shows, circles having the same centre; the figure enclosed by the circumferences of two concentric circles is an " annulus " (fig.
In another Pecopteroid genus, Sturiella, the synangia resemble those of Asterotheca, but each sporangium is provided with a band of enlarged cells of the nature of an annulus (fig.
in length, and had a multiseriate annulus, extending, however, to both sides of the sporangium (see fig.
In Stauropteris, a genus showing some affinity with Zygopteris, the branched rachis of the fertile frond terminates in fine branchlets, each bearing a single, spherical sporangium, without any differentiated annulus (fig.
Then consider a thin annulus thin of the wire of width dx; the charge on it is equal to thin rod.
21rry/dx units, and the potential V at a point on the axis at a distance x from the annulus due to this elementary charge is ll2 2?rrc V=2 j o (r2+x2) dx=47rrvj log e (2l+1,/ r2 +412 ') - loge'} If, then, r is small compared with 1, we have V =47rry log e llr.
a, The annulus, or remnant of B, The mature plant.
The sporangia (pollen-sacs), which occur on the under-side of the stamens, are often arranged in more or less definite groups or sori, interspersed with hairs (paraphyses); dehiscence takes place along a line marked out by the occurrence of smaller and thinner-walled cells bounded by larger and thickerwalled elements, which form a fairly prominent cap-like " annulus " near the apex of the sporangium, not unlike the annulus characteristic of the Schizaeaceae among ferns.
The annulus is horizontal and the dehiscence median.
Each has an almost horizontal annulus resembling that of Gleichenia, but the dehiscence is lateral.
The dehiscence of the sporangium is almost transverse, as in the Polypodiaceae, but the annulus is slightly oblique.
3, C); at the base of the cone an outgrowth of the axis like a rudimentary leaf sheath (the annulus) is present.
names are sterile, and can not be assigned to a particular family, but some are undoubtedly sporangia with an apical annulus (" monangic sori " of Prantl) on either side of the midrib.
It has been found by Sir William Herschel and others that the definition of a telescope is often improved by stopping off a part of the central area of the object-glass; but the advantage to be obtained in this way is in no case great, and anything like a reduction of the aperture to a narrow annulus is attended by a development of the external luminous rings sufficient to outweigh any improvement due to the diminished diameter of the central area.'
The sporangium, which corresponds on the whole to that of the Gleicheniaceae, has a somewhat oblique annulus; the dehiscence also is not truly median.
The sporangia, which arise in basipetal succession on the receptacle, dehisce by a median slit, though the annulus is somewhat oblique; they have resemblances to the Gleicheniaceae.
Numerous more or less isolated fern-sporangia occur in the petrified material of the Carboniferous formation; the presence of an annulus is a frequent character among these specimens, while synangic sori are rare; it is thus certain that families remote from the Marattiaceae were abundantly represented during this period.
B, Single sporangium, in transverse section, showing annulus on both sides, magnified.
The word usage examples above have been gathered from various sources to reflect current and historial usage. They do not represent the opinions of YourDictionary.com.