84 MR. MIERS ON THE OUTER FLESHY COVERING OF THE SEED 
vessels of the raphe penetrating the outer coating at the hilum, that is to say, at the 
extremity diametrically opposite to that of the original gangylode, and after running 
along its inner surface, they find their way straight to the diapyle of the enclosed nut, 
through which they pass to lose themselves in the chalaza of the inner integument, both 
which points in the ripe seed (the diapyle and chalaza) correspond with the gangylode of 
the ovule. - 
I have endeavoured, by the accompanying figures, to render this question manifest. 
Plate XIX. figs. 56 & 57 represent an ovule of Magnolia after Dr. A. Gray, showing the - 
broad placentary sheath which encloses the spiral vessels of the raphe. Fig. 58 is a longi- 
tudinal section of the same, showing that the spiral vessels originate at the placenta and 
hilum, and that they terminate at the opposite extremity, at the point of the gangylode, 
which is the only point of the primine where these vessels traverse, in order to convey 
nutrition to the secundine and nucleus: it is here evident that the sheath or extension 
of the placenta containing these spiral vessels, must always remain exterior to the primine, 
as well as to the tunic resulting from its subsequent growth. Fig. 59 shows a section of 
the ripe seed of Magnolia, where the placentary sheath (seen in fig. 58) during the incre- 
ment of the ovule, has in the progress of its own growth, extended itself all over the 
primine, and has become enlarged into an arilliform scarlet coating, and we have proof 
that this coating is the result of such growth, by the fact that the raphe, retaining the 
same position and direction, still remains enclosed in its substance. The primine, during 
its increment, by the deposition of osseous cells within it, in the manner recorded by 
Dr. Gray, becomes converted into the bony testa, shown in figs. 60 & 61, where the diapyle 
or aperture is seen in its apex for the passage of the raphe, corresponding with the same 
point of the gangylode in the ovule, through which these same vessels there penetrated : 
we have evidence that this testa is the product of the primine, not only from this circum- 
stance, but because it is exterior to another integument, the tegmen, which covers the 
albumen, and which exhibits a chalaza in its apex, as seen in fig. 62. The above gives 
us an example of the development of the simple raphe. 
As an instance of a branching raphe, I will select the seed of Licania, shown in fig. 63; 
this has à basal hilum, and is the growth of an anatropal ovule. Referring to figs. 56 & 58, 
it is evident that the only point where the spiral vessels can enter the primine, is at the 
gangylode, the point which they passed through prior to the inversion of the ovule. If, 
a ss the hypothesis of Dr. Gray, the raphe insinuated itself into the 
en —— " must, in the case Of Licania, begin to send out its ramifi- 
nn a å «Suk it entered, that is to say, from the gangylode; but on the 
en nn à - + e vessels start from the opposite point of the hilum : the main — 
lar aig course (as in the case of the simple raphe) to the gangylode or 
DE » Mrowing out its redundant vessels in many lateral branches, while other 
the tunic resulting from its growth, that they must have 
th and have pierced their way through the outer pellicle 
hemselves into its substance at a point near the micropyle, 
