90 MR. MIERS ON THE OUTER FLESHY COVERING OF THE SEED 
greater probability, that the extraneous coating is produced from the funicular cord, 
rather than from the foramen or micropyle of the primine, and in such case the arillode 
i the aril. 
ces TR of examining the ovule during its growth, but have lately 
observed ripe and living seeds of Ewonymus Europæus. Here the outer coating is entire 
fleshy and scarlet, with a smooth inner skin, and we find beneath it, another polished, 
thinner, though somewhat fleshy tunic, that closely adheres to the seed. If this tunic be 
removed carefully from the thin pergameneous testa, it will be found to consist of two deli- 
cate reticulated pellicles, having cellular and fleshy matter interposed between them, the 
raphe being completely immersed in its substance, in the form of a ne cord, which 
originating at the basal hilum, proceeds along its face to the apex, where 3t pierces the 
inner pellicle of this tunic, passes into a small opaque speck in the summit of the testa 
(the diapyle), and is lost in the chalaza of the inner integument which is adherent to the 
shell. Here we have demonstrative evidence of the nature of these several envelopes ; 
the outer coat is manifestly a true and entire aril, for we cannot suppose it to be a deve- 
lopment of the primine, that is to say, an extension of its exostome, as Dr. Planchon 
almost doubtfully concluded, because it is altogether free from, and exterior to a more 
internal tunie which encloses the raphe: it follows, therefore, as a necessary Consequence, 
from the position of the nourishing vessels, that it must be a production emanating from © 
the main placenta or a growth from the funicular support of the seed. The fleshy 
epidermoid tunic which encloses the raphe, and which immediately invests the pergame- 
neous shell, appears to be an arilline, resulting from the growth of the placentary sheath : 
the thin pergameneous shell is, of course, the true testa, marked at its base by a small 
prominent nipple, close to the hilum, which is no doubt the thickened border of the true 
. mieropyle figured by Dr. Planchon, and from which he inferred that the growth of the 
aril had emanated: the apical speck through which the vessels of the raphe penetrate, is 
the diapyle: it is hardly necessary to add, that the radicle of the embryo, enclosed in 
albumen, points to the micropyle, while the extremities of the cotyledons are directed 
towards the diapyle. I do not find the aril pervious in the apex, as stated by Gærtner, 
and as figured by Dr. Planchon in another species, although this, no doubt, sometimes 
occurs; but in the instance above mentioned, the inner skin of the tunie, though slightly 
crumpled, is entire, while its outer pellicle is deeply plicated in flattened folds, so that 
the aril appears cleft into numerous fissures externally. 
Among the many interesting facts detailed by Dr. Planchon in the work just quoted, 
we meet (Joc. cit. p. 25) with an account of the circumstances under which the seeds of 
Opuntia become covered by two distinct extraneous envelopes, both exterior to the testa : 
the first is a somewhat thin, hard, coriaceous tunic, aecording to his observations; the 
second is a soft, mucilaginous, pulpy coat by which the former is encircled. The growth 
of the former was traced by Dr. Planchon from the period of the anatropal inversion of 
the ovule, which was carried to an extent of a complete gyration, so that the placentary 
sheath I have before described, appeared at first like an annular band around the 
periphery of the ovule; from this ring, on both sides, 
membranaceous expansions were 
seen gradually to extend themselves over the interve 
ning spaces, until they met in the 
