VAUCHERIA. 49 



douce," the following observations occur. Alluding to the 

 horns, Vaucher observes -- " At first they are straight and 

 opaque, and consequently contain the green fecundating 

 matter; gradually they incline towards the grain, and surround 

 it, so that they rest upon it to shed their powder. When 

 the seed is separated, they are empty, and assume a spiral 

 form ; and what confirms me still more in the opinion, that 

 the horns fulfil the functions of stamina is, that all the Ec- 

 tosperms which are provided with them have no other en- 

 largement, and that, on the contrary, those which have other 

 enlargements are altogether destitute of the horns." 



If the horns approach the seeds in some cases, the con- 

 verse is true in others ; and the propriety of this will be 

 evident when we consider the position of the horns with 

 reference to the grains or 'germs in some species. In Vau- 

 cheria geminata, the germs which are furnished with pe- 

 duncles approach the horns, in contact with which they 

 remain for some hours, and then gradually they raise them- 

 selves from it, and the peduncles which support them curve 

 backwards away from the horns. This gradual approach of 

 the grains to the horns, and their subsequent retraction from 

 them, strengthen the conclusion that this organ is necessary 

 to the grains. For Voucher's assertion to be correct, that the 

 horns approach the grains in the case where there is but one 

 anther, situated midway between two spores, it would first 

 have to turn towards and reach the one spore, and then act 

 in like manner towards the other ; the improbability of which 

 is self-evident ; but, on the other hand, how simply are the 

 germs brought within the influence of the horn by their ap- 

 proach to it on each side. 



The " other enlargements " in which the horns are absent, 

 referred to by Vaucher, I presume to be terminal enlarge- 

 ments of the threads, as in Vaucheria clavata, and which are 

 altogether of a different nature from the capsular bodies de- 

 scribed. Oval inflations of the filaments do also occur occa- 

 sionally : the presence of these, however, is by no means 

 constant, and they do not seem to be in any way connected 

 with reproduction. 



