There is, in birds, no annulus tympanicus.
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.
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.'
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.
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.
The figure Abdc is a sector of an annulus, which is the portion of a circle left after cutting out a concentric circle.
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.
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'.
" 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.
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.