( cxiii ) 



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 Acrseinse. 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 uptil 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 hetei'ostyled plants. 80 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 



PEOC. ENT. see. LOND., V. 1903. I 



