96 MR. J. SCOTT ON THE FUNCTIONS AND STRUCTURE OF THE 
with the results, which are certainly most astounding ; inasmuch 
as each of the sexual forms of a species manifest in their respec- 
tive powers for conjunctions with those of another species, phy-. 
siological peculiarities which might well entitle them, by the 
criterion of fertility, to specific distinction. 
There is another interesting point illustrated by the above ex- 
periments upon which I will venture a few remarks—subject to 
the reservation, however, of their being modified by more nume- 
rous experiments. It is now perfectly well known that the two 
forms of several species of Primulas have their sexual powers 80 
correlated, that while very imperfect fertility results from the 
fertilization of either form by own-pollen (a homomorphic union), 
perfect fertility results from the application of the pollen of the 
one form to the stigma of the other (a heteromorphie union). 
In the present instance, then, we are naturally led to inquire 
whether these correlations of the sexual powers in the two forms 
of a species extend in parallel lines to the two forms of a distinct 
species when hybridized? or are they limited in their opera- 
tion to the individual forms of the species? In other words, 
in the hybridizing of dimorphic species, is the heteromorphic 
definitely more fertile than the homomorphie union? or is the 
alternative innately variable? Let us again, for a moment, recur. 
to the above details and Table of hybrid unions for a little en- 
lightenment on these queries. First, we see the short-styled komo- 
morphic union of P. Auricula by pollen of P. viscosa, highly fertile ; 
while of the other three unions tried between these species (two 
heteromorphic and one homomorphic), not one flower produced a 
seed-capsule! Again, secondly, successful results are derived from 
the long-styled heteromorphic and the short-styled komomorphie 
unions of P. Auricula by pollen of P. hirsuta,—the heteromorphic 
yielding more seed than the homomorphic in the proportion of 
4to3. The other possible unions of these forms (three hetero- 
morphic and three homomorphic) were also tried; but they did not ` 
produce a single seed-capsule! What now do these several expe- 
riments teach us respecting the points at issue? Looking to thé 
successful experiments alone, we might be inclined to suppose, 
from the result of P. Auricula and P. hirsuta, that in the hybrid 
unions, as well as in the cross-unions of the two forms of a species, 
the heteromorphic were the more fertile, —even with the remark- 
able fertility of the short-styled homomorphic unions of P. Auricula 
and P. viscosa staring us in the face. On the other hand, if we 
take a general view of the evidence, and carefully balance and 
