550 
APPENDIX. 
[B. 
rishing vessels and channel through which fecundation took 
place in the ovulum, may still be seen in many of those ripe 
seeds that are winged, and either present their margins to 
the placenta, as in Proteacese, or have the plane of the wing 
at right angles to it, as in several Liliacese. These organs 
are visible also in some of those seeds that have their testa 
produced at both ends beyond the inner membrane, as Ne- 
penthes ; a structure which proves the outer coat of scobi- 
form seeds, as they are called, to be really testa, and not 
arillus, as it has often been termed. 
The importance of distinguishing between the membranes 
of the unimpregnated ovulum and those of the ripe seed, 
must be sufficiently evident from what has been already 
stated. But this distinction has been necessarily neglected 
by two classes of observers. The first consisting of those, 
among whom are several of the most eminent carpologists, 
who have regarded the coats of the seed as products of 
fecundation. The second of those authors who, professing 
to give an account of the ovulum itself, have made their 
observations chiefly, or entirely, on the ripe seed, the coats 
of which' they must consequently have supposed to be formed 
before impregnation. 
The consideration of the arillus, which is of rare oc- 
currence, is never complete, and whose developement takes 
place chiefly after fecundation, might here, perhaps, be en- 
tirely omitted. It is, however, worthy of remark, that in 
the early stage of the ovulum, this envelope is in general 
hardly visible even in those cases where, as in Hibbertia 
volubilis, it attains the greatest size in the ripe seed ; nor 
does it in any case, with which I am acquainted, cover the 
foramen of the testa until after fecundation. 
The testa, or outer coat of the seed, is very generally 
formed by the outer membrane of the ovulum ; and in most 
