the Ovula of Loranthus and Viscum. _ 77 
7. That the embryo is at first included in the ovulum; that in Loranthus 
the funiculus subsequently becomes very short, and the apex of the embryo 
naked. 
8. That the cotyledons, in some, become subsequently united, except at 
their bases, and in such two lateral slits are visible externally. 
General Remarks. 
From what has been stated, it will appear that the ovulum is, both in Lo- 
ranthus and Fi iscum, a formation subsequent to impregnation. This remark- 
able, and, I believe, unparalleled fact, will tend materially to increase the 
difficulty of understanding or even conjecturing the nature of the first steps in 
the formation of an embryo. It is evident that it is at total variance with the 
idea that the ovulum, or female organ, is a nidus adapted to, and necessary 
for the development of the embryo, which in this view is supposed to be 
derived entirely and directly from the male. It is needless to add, that it is 
totally different from the usual development of ovula. 
With respect to the first part of the process of development, I may observe 
that original continuity of tissue is very general, and perhaps universal. And, 
in particular, I believe the nucleus of an ovulum to be ab origine solid ; what- 
ever is produced subsequently in its interior being developed in a cavity formed 
by an excavating process. ; 
Although there can be no doubt from its structure and functions, that the 
fleshy body in which the mature embryo is more or less contained is albumen, 
yet it may be proper to state in what part of the tissue the necessary change 
is carried on; particularly since there is, I believe, no instance of albumen 
occurring as a primary formation *. | 
The albumen in both these genera may, therefore, be classed with those 
* Although I have not proved the existence of a sac in Loranthus, within which the tissue which 
subsequently becomes the albumen, is formed, yet, from the consideration of Viscum, and from the 
obvious analogy which its sac presents to the sac of the amnios in ordinary structures, I have little 
hesitation in advancing the opinion that the ovulum in Loranthus and Viscum is reduced to its simplest 
possible state, and that the albumen is a deposit within the tissue of the amnios, the sac of which has 
at an early period ceased to exist, at least as a distinct membrane. Further researches may hereafter 
establish the fact of the amnios being the only essential part of an ovulum. 
