INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 933 



is of a cyliudrical form, abruptly rounded off at the extremity, and its 

 narrow interior canal is filled with colourless, finely granular proto- 

 plasm. The trichogyne is most important, as it is the receptive organ, 

 analogous to the elongated style which occurs in so many phanero- 

 gams. Fresh antherozoids of Polysiphonia subulata, on coming into 

 contact with the upper part of the trichogyne, which seems to some 

 extent to act as a stigma, immediately adhere to it firmly, when the 

 granular contents of the antherozoid pass into the interior of the 

 trichogyne, and a part of them descending the canal in the latter reach 

 the carpogonium, of which they fertilize the central cell. This pro- 

 cess, as will be seen, is very analogous to that which takes place in 

 phanerogamous plants. 



In the case of anemophilous or wind-fertilized dioecious plants, it 

 is well known that the chance of fertilization is usually greatly 

 increased by the enormous quantity of pollen which the male flowers 

 yield to every passing breeze, and a similar provision is found to 

 prevail in the case of dioecious Polysiphonia. It is perfectly clear 

 that the antherozoids of this plant, being quite destitute of any loco- 

 motive organs, must be passive in their further proceedings, and they 

 are no doubt carried along in all directions by the currents and other 

 movements of the water until, on meeting with the trichogyne of the 

 female plant, they adhere to it, and fulfil their duty. When the two 

 sexes grow at no very great distance apart. Professor Dodel-Port 

 seems to think that the small marine animals, Crustacea, annelids, star- 

 fish, infusoria, &c., which swarm in the submarine forests of Florideaa, 

 may aid importantly in effecting the transportation of the fertilizing 

 element to the female organ ; but in the course of his investigations 

 he discovered that certain minute animals interfere in the process in 

 a much more curious and interesting fashion, vividly reminding us, 

 indeed, in the singular adaptation of means to ends, of the wonderful 

 relations unquestionably existing between insects and flowering plants. 

 On the growing thallus, and especially on the youngest branches, 

 Prof. Dodel-Port constantly found an immense number of the well- 

 known bell-animalcules ( Vorticella), which were, as usual with them, 

 in incessant motion. These little creatures were found to feed upon 

 the antherozoids floating about in the water ; but besides those which 

 they manage to swallow, a considerable number are whirled about in 

 the vortex caused by the cilia of the animalcule, which no doubt stops 

 them in the course impressed upon them by larger submarine currents, 

 and keeps them, as it were, hovering about the neighbourhood where 

 their business lies. As the VorticellcB are constantly changing their 

 position by the contraction and extension of their little foot-stalks, the 

 whirls set up by them in the water must become very complex, and 

 the best proof that the action of these little vortices upon the anthero- 

 zoids is beneficial to the plant, is to be found in the fact that it was 

 through their agency that the author was enabled to observe the 

 attachment of the antherozoids to the trichogyne. The presence of 

 the VorticellcB, in fact, imparts to the passive antherozoids a motion 

 analogous to that with which the ciliated sperm-cells of other Algge 

 are endowed. In the case of the Polysiphonia, the beneficial action of 



