MR. JOHN MIERS ON A NEW GENUS OF THE BURMANNIACEZÆ. 469 
“ mucous-tubes, ” first apparent on the stigma, which gradually extended themselves 
through the style in a bundle like a cord, which, on reaching the summit of the ovary, 
there became divided into three lines running parietally along the sides of the cell ; and on 
reaching the beginning of the three placentæ, each line again divides into two branches, 
which run along the sides of the placenta (p. 706); and he noticed the extremities of 
many of these ** mucous-tubes "' scattered over the surface of the placenta (p. 742). At 
first he took these “ mucous-tubes” to be pollen-tubes, (p. 739), but he afterwards 
retracted that opinion. He states that, in size, in number, and in appearance, they so 
greatly resemble them, “that they are with difficulty distinguishable” from them 
(p.741). Having traced these **mucous-tubes" to the sides of the placentæ, he re- 
marked that those which were scattered over their surface became remarkably and irre- 
gularly flexuose (p. 743) ; and in not a few cases he traced them into the mouths of the 
ovules, to which they adhered with considerable firmness [p. 742]. The fact “that the 
tubes thus traced to the foramen of the ovules are of the same nature as the mucous- 
tubes, and not those produced directly by the pollen, was proved [to him] by their 
exact agreement with the former in every respect ” (p. 743), except by not being granu- 
lar on their surface and distinguished by having generally those interruptions in the 
cavity, formed of a substance which he termed “ coagula,” and which he never met with 
in the tubes actually adhering to the grains of pollen (p. 741). In his concluding re- 
marks, he states that the two most important facts, which he considered to be the ré- 
sumé of his researches, are, 1, “the produetion of tubes not directly emitted from the 
grains of pollen, but apparently generated by them” (or, to have spoken more correctly, 
which become visible at the period of the emission of the pollen-tubes and their appli- 
cation to the stigma, as shown in p. 739), and, 2, “the introduction of one, or some- 
times more than one of these [mucous] tubes into the foramen of the ovule" (p. 743). 
We may deduce from these facts, that the * mucous-tubes," here so minutely described, 
and to the agency of which so much importance is attached, are the stigmatie channels 
accurately described by Mirbel under the name of “ vaisseaux conducteurs de l'aura 
seminalis” *, as contradistinguished by him from the * vaisseaux nourriciers" of the pla- 
centa (which extend to the funicle of the ovules), and that the extremities of the ** mu- 
“us-tubes ” which spread over the placenta, and where they become much curved, con- 
stitute that peculiar fringe-like tuft called “ tele conductrices,” some of which tubes were 
‘een by Mr. Brown to enter the foramen of the ovules, and there become agglutinated 
to them (l. c. p. 742)—a circumstance that should be especially Zee Si 
v rn fringe of tissue is to conduct the en en transmitt re 
ough the “ mucous-tubes” to the apex of the 0 , guit À 
red Portrayed in the great number of cases figured by m RE nde t im 
hs i matis, where the mouths of the ovules, x the voten um p ue described by Mr. Brown 
ý li fringe-like tuft. In fine, there is not a single fa D au Me pollen-tabe 
celebrated memoir to prove, nor an opinion stated to show, 
ever Li “A 
reaches an ovule in the Orchidaceae. 
—this adaptation being 
* Mém, de l’ Acad, vol. ix. p- 633. s 
VOL. xxv, : 
