OF THE OVARIUM OF SIPHONODON. 135 . 
the rounded shoulders of the column, in others not till after it has enveloped that organ. 
It is at this period, however, that the important difference between my observations and 
Mr. Griffith’s occurs, and as it is upon this that the whole question of the placentation 
turns, I have taken every means of endeavouring to arrive at the truth. Griffith says, 
that at the period when the base of the central column becomes concealed by the growth 
of'the annulus, very young ovula may be detected, apparently attached around the whole 
base of the column, and not presenting any manifest relations with the carpellary leaves. 
He adds, that at this time a double long section had not shown him any solution of 
continuity resulting from foreibly pulling back the carpellary leaves (annulus) and thus 
exposing the ovula. On the other hand, I, at no period, find the ovules to be developed 
freely at the base of the column; I have sought in vain between the annulus and column 
for any such appearance, removing the annulus piecemeal with the utmost caution; and 
in every double vertical section that I have made, I have found the ovarian cavities to be 
developed even at a much earlier period than that indicated by Griffith, below the junction 
of the annulus and column, manifestly within the substance of the ovary. The cavities 
containing the ovules cannot at any period be exposed without tearing the annulus, which, 
however, owing to the delicacy of the tissues and the excessive mfnuteness of the organs, 
it is sometimes difficult to avoid doing. 
3. In the succeeding stage (fig. 5), the anthers are fully formed, ånd, arching inwards, 
conceal the whole vertex of the ovary, leaving the apex of the column alone exposed 
between their apices (fig. 8). The eylindrical portion of the column has lengthened, and is 
terminated by a capitate stigma-like head; its conical base is proportionally smaller and 
more depressed. The annulus is very much thickened and grown in all dimensions; it 
has advanced up the column, and presents on a double vertical section two broad shoulders 
embracing the column, which it thus sheaths in a tube; its upper surface is moulded by 
the pressure of the anthers which lie between the five radiating ridges accurately described 
by Griffith. The five teeth (figs. 8? & 64) terminating the ridges are now more promi- 
nent, turn upwards, and are very cellular and fimbriated; and a distinct groove is formed 
on the surface of the annulus, close to its orifice and concentric with it. The ovarian 
cavities are fully formed, linear-oblong, and all point outwards, but some upwards and 
some downwards. The ovules are horizontal with an obscure lateral raphe, and each is 
conformable to its cell. The column has an evident cuticle, as has also the contiguous wall 
of the annulus. At this period vascular bundles appear in the ovary, and are traceable 
downwards from each ovular insertion, and transparent lines are continued from each 
ovule upwards into the annulus, to whose inner face these ascending lines are parallel and 
contiguous. The tissues of the sheath of the annulus are pale and translucent. Mr. 
Griffith says, that at this period the stigmatic surfaces will be found at the conical base of 
the central column, at the point of its junction with the base of the annulus; he says, 
«the lines of communication, by which each isolated ovulum is placed in the usual con- 
_ ditions to receive the male influence, will be found to terminate on the circumference of 
the conical base of the central column.” On the contrary, I find the cuticle to be uni- 
formly extended over the points indicated; but its tissue is there rather looser, the cells 
which form it being elongated inwards, giving when torn the appearance of stigmatie 
