*, 
86 MR.J. SCOTT ON THE FUNCTIONS AND STRUCTURE OF THE 
elements,—coincidences certainly not without an interest from a 
theoretical point of view. I have also noticed a few other genera, 
which, though not reciprocally dimorphie in structure, never- 
theless present such relative inequalities in the length of their 
stamens and pistils, that certain external agents are absolutely 
necessary to induce anything like perfect fertility. In this ar- 
rangement of the sexual organs, then, it is evident that a better 
chance is afforded for the crossing of individuals than is the case 
in that arrangement where an equality in the length of the latter 
organs is observed. Thus nature presents us, as it were, with 
one of her simplest plans for effecting what Mr. Darwin on a 
thoroughly philosophical basis regards as one of the great ends 
gained by that more complex and novel plan in which she so 
differentiates the sexual elements of individual hermaphrodites, 
that the conjunction of these from distinct individuals is rendered 
imperative for the accomplishment of perfect fertility. In respect 
to the other genera of the order which I have examined, I observed 
nothing in the structural relations of the sexual organs worthy 
of special notice; this, however, is exclusive of the following 
genera, of which I know nothing— Zubinia, Apochoris, Pelletiera, 
Asterolinum, Euparea, and Micropyzis. 
I will now give in detail my observations and experiments on 
several “ dimorphic ” and * non-dimorphic" species of Primula, The 
former of these, as previously stated, has been specially treated by 
Mr. Darwin, who, as might be expected, has left little for sub- 
sequent elucidation. This, indeed, is so much the case, that I 
fear my observations will do little more than show that the di- 
morphism manifested by those species to which Mr. Darwin’s 
observations were directed is common to many more. It is, there- 
fore, with no pretensions to originality that I venture to lay the 
following observations before this Society. However, as the phe- 
nomena of reciprocal dimorphism is comparatively new to science, 
further elucidations of it will not, I trust, be deemed superfluous. 
Primula Auricula.—The dimorphic structure of this species has 
been fully described by Mr. Darwin, and we might anticipate, 
from the results of the few experiments he has made on this 
species, a functional dimorphism similar to that he has so ably 
illustrated in Primula vulgaris, veris, and Sinensis. I there- 
fore had no intention of giving in detail the results of my experi- 
ments on the unions of the two forms of this species. My atten- 
tion, however, has been lately directed to a tacit implication of 
the absolute sterility of the long-styled form. As this view is 
