126 MR. J. SCOTT ON THE FUNCTIONS OF THE PRIMULACEE. 
morphie about twenty-four seeds per capsule, whereas the form 
with stamens and pistils of an equal length yields, when fertilized 
with its own pollen, thirty-four seeds per capsule! Thus the non- 
dimorphic form by own pollen exceeds, first, the homomorphie 
unions in the proportion of 5 to 2, and secondly, the hetero- 
morphic in the proportion of 3 to 2! Again, from the four different 
unions of the long- and short-styled forms with the non-dimorphic 
form, the seed-results in each case fall considerably below an 
ordinary homomorphic union: thus the mean results of the 
unions of the non-dimorphie with long- and short-styled are six 
seeds per capsule, whereas the pure homomorphic unions of the 
latter give an average of thirteen seeds per capsule—that is, as 
two to one! 
Connected with these are the remarkable changes in the fer- 
tility of the coloured varieties of the Primrose, the red variety 
yielding no seed when fertilized by pollen of either yellow or 
white varieties: the reciprocal crosses of these, i.e. the pollen 
of the red variety applied to the stigmas of the yellow and white, 
are also absolutely sterile! On the other hand, fertile unions may . 
be effected by the reciprocal erossing of the yellow and white 
varieties, though in every ease we have found that the average 
seed-result of such unions is considerably under that of the pure 
unions of these forms. 
Whether or not the ultimate tendeney of dimorphism is a com- 
plete separation of the sexes, I think we have the clearest testimony 
that dimorphism has not always been a genealogical characteristic ; 
and furthermore, that the two forms did not per saléwit assume 
these structural and physiological characteristics. I here allude to 
the evidence afforded by the non-dimorphie Cowslip—namely, the 
resumption of perfect hermaphrodism, and the occasional produc- 
tion of intermediate stages between this and the normally dimor- 
phie. These, taking us back in the genealogical line, show us an 
original non-dimorphie progenitor, and the graduated plan by 
which it gave rise to a dimorphically characterized race. 
