( 45 ) 
can be carried on under the most favourable conditions, so 
our chief museums should be provided with the means of 
establishing temporary stations in the most favourable parts 
of the tropics. When I say temporary, I do not refer to the 
means, but to the position of the station, which should be 
freely movable in response to the call of important problems 
as they present themselves for solution in other localities. 
Another urgent reason for the establishment of biological 
stations is forced upon us by the inadequacy of diagnosis for 
the separation of very variable species, such as many of the 
African Acraine. I cordially agree with the view often 
expressed to me by my friend Mr. F, A. Heron, that we shall 
never reach a secure foundation until synepigonic series have 
been obtained on a large scale. To achieve this end a 
temporary station would be required. In this way our 
museums could receive, and should keep for permanent study, 
the whole of the offspring reared from the eggs of a single 
parent. If several species were thus represented by one or 
more large synepigonic series, we should know what to expect 
and what to allow for; and diagnosis in general would gain 
the most helpful guidance. 
Asyngamy, as regards particular lines of union, has also 
been incidentally brought about by certain adaptations 
for cross-fertilisation in plants, and such asyngamy has in 
some cases persisted long enough to have led to sterility in 
greater or less degree. Of all Darwin’s work, that upon 
the fertilisation of heterostyled plants threw most light, he 
considered, upon sterility between species. As Francis Darwin 
has stated, “ He found that a wonderfully close parallelism 
exists between hybridisation and certain forms of fertilisation 
among heterostyled plants. So that it is hardly an ex- 
aggeration to say that the ‘illegitimately ’ reared seedlings are 
hybrids, although both their parents belong to identically the 
same species. In a letter to Professor Huxley, given in the 
second volume [of ‘Life and Letters’], p. 384, my father 
writes as if his researches on heterostyled plants tended to 
make him believe that sterility is a selected or acquired 
quality. But in his later publications, e.g. in the sixth 
edition of the ‘Origin,’ he adheres to the belief that sterility 
