PREFACE. XXXV 
the first extention of the vessels of the placenta 
into the ovulum. It is a general law that every 
part of a vegetable is aborigine cellular, the exis- 
tence of a vascular system or of any system analo- 
gous to it in function being called into play ata 
subsequent period, and being a test in every sense 
of the word of complete evolution. Instances are 
not wanting where the seeds are certainly evascular, /n 
others, the absence of vessels is supplied by elong:-ed 
tissue. The vascular system of ovula is se'xXom, 
perhaps never complete until aften fecundaticz, and 
it is very provable that the drawings wbéch re- 
present in such cases a distinct raphe are errone- 
ous. [tis most complete in those ovula in which 
the inversion above mentioned has taken place, the 
ovules anatropes of M. Mirbel. In most instances 
in which a vascular system does exist a direct 
communication is effected between the placenta and 
the base of the nucleous, around which in some 
instances the ultimate vessels in some radiate. It - 
hence follows, that a raphe is not limited to the 
anatropous form of ovula, neither Are the vessels 
confined to the testa, although it is an indispu'able 
fact to which however I know of one exception T 
that the second integument (scarcely as it is not the 
second but probably the embryonary sac which is vas- 
cular) is, with the exception of that part of the 
base, perforated by the vessels in their course to the 
base of the nucleus, certainly cellular 
In those instances in which the base of the nuc- 
leous and of the integuments correspond with the 
