( 396 ) 



Kut besides the function, discovered by Bonnier and the signi- 

 ficance of the secreted nectar for the fertilisation, it has become 

 clear to me that as well the glucose, formed from saccharose, as 

 the outwardly secreted nectar, are also in other respects of great 

 importance to the plant. The observations, here communicated, point 

 already to one very important function, i. e. to enable the stamens 

 to bring their pollen to the surface at the right time, independent of 

 the hygroscopic condition of the air. 



I hope before long to be able to point out still another function. 



The secretion of nectar now appears in another light. The view 

 that it must be considered as an excretion of "a waste product of 

 chemical changes in the sap" ^), which in the course of time has become 

 more marked through natural selection, as a useful adaptation for 

 promoting cross-fertilisation, since this liquid was eagerly taken away 

 by insects, has to give way to the conception that, preceding any 

 adaptation, it has in its further development kept pace with the 

 sexual organs. 



Anatomy. — "On the relation of the genital ducts to the genital 

 gland in marsupials." By A. J. P. v. d. Broek. (Communicated 

 by Prof. L. Bolk). 



(Communicated in the meeiing of October 27, 1906). 



In the following communication the changes will be shortly described 

 which the cranial extremities of tlie genital ducts in marsupials 

 undergo during the development and their relations in regard to the 

 genital gland. In more than one respect the ontogenetic develop- 

 ment differs in these animals from what can be observed in other 

 mammals. 



It is especially a series of young marsupials of Dasyurus viverrinus 

 in successive stadia of development from which the obsei'vations are 

 derived. The preparations of other investigated forms (Didelphys, 

 Sminthopsis crassicaudata, Phascologale pincillata, Trichosurus vulpe- 

 cula, Macropus ruficollis) correspond however completely with the 

 conditions we meet in Dasyurus. 



In our description we start from a stadium schematically represented 

 in figure 1 that still prevails for both sexes, (Dasyurus, Didelphys, 

 Macropus). The genital gland (Figure 1 k) is situated at the medial 



1) Ch. Darwin. Origin of species. Sixth Edition. 1872. Chap. IV, p. 73 and 

 The effects of Gross and Seitferlilisation. Edition 1876, Chap. X, p. 402. 



