108 MR. MIERS ON SEVERAL INSTANCES OF ANOMALOUS DEVELOPMENT 
narrow basal extremity, which is enclosed in a short fleshy sheath, part of the funicle, from 
which it has broken away, and by which it is connected with the placenta, and suspended 
in the pulp of the fruit: a groove runs parallel with the margin on each face close to the 
periphery, forming in this manner a prominent zone all round the edge of the seed, which 
is broader towards the base, and which thus forms a short auricular expansion on each 
side of the hilum. On a former occasion (p. 92) I described the outer crustaceous 
tunic, hitherto considered as the testa, but which I shall prove to be of the nature of an 
aril, formed subsequently to the fertilization of the ovule, around its original integu- 
ments : it was there shown to be formed of three series of deposits, the epiderm, meso- 
derm and endoderm: the epiderm is a thin delicate membrane that covers the whole of 
the seed, and is extended beyond the hilum in the manner above-mentioned, as an exten- 
sion of the sheath of the umbilical cord; the fleshy mesoderm has been before deseribed, 
its numerous branching fibres being emanations from the bundle of simple vessels that 
fill the sheath of the funicular cord, and that surround the thread of spiral vessels pro- 
ceeding from the placenta, that terminates in the raphe of the seed; the principal portion 
- of the tunic is the endoderm, which is, in fact, a crustaceous compressed sac, enclosed in 
the above-mentioned vesicular terminal enlargement of the sheath of the umbilical cord ; 
it forms a casing closed all round the seed, except at the hilum, where it has a long open 
slit, within the mouth of which is a considerable open space filled with pithy loose cel- 
lular tissue, which fills up this interval between the pointed extremity of the enclosed 
nucleus and the mouth of the crustaceous covering: there is no connexion whatever 
between any part of this crustaceous coating and the enclosed seed, which lies quite free 
within it, and fills up its cavity. The raphe, consisting of a number of spiral vessels 
enclosed in a delicate tube, is first seen to issue from the umbilical cord; it then finds its 
way through one of the basal auricular lobes of the endoderm, in which a channel is seen _ 
for its passage, after which it enters into the clear space between this crustaceous aril 
and the integuments of the contained seed, and under the form of a perfectly free delicate 
white thread, it runs all round the margin of the seed, forming a complete circle, until it 
again reaches the space within the mouth of the hilum, and when in the midst of the 
deposition of tissue before mentioned, it changes its course suddenly inwards, and termi- 
nates in the conical neck of the integument of the seed, by which the latter becomes thus 
suspended : this conical neck is of a dark brown colour, and is evidently the true chalaza 
of the integument. The covering of the enclosed seed is thin and membranaceous, gene- 
rally of a greenish hue, is quite smooth and evidently composed of two, if not of three pelli- 
cular membranes, agglutinated into one thin integument. I have sometimes found this 
structure more clearly demonstrated where the nucleus has become withered from its 
fall ‚dimensions ; it then appears as a large, perfectly transparent cyst, enclosing the 
oR aang = by transmitted light displays the deeper colouring of the chalaza 
irent si this re which “ppears surrounded by another pellicle more trans- 
sn — à ect aig of the spiral vessels in the suspending thread, up to the 
Bits. covering-of the = Pa ere perfectly distinct. At the other end of the integu- 
digo tack edm es » the one contrary to that of its suspension, is seen another 
6, over the cotyledonary extremity of the embryo, and therefore 
