104 i REPORT— 1898. 



2. On the Form of the Protoplasmic Body in certain Floridece. 

 By Reginald W. Phillips, M.A., Bangor. 



In Ceramiinn riihnnn and other species a strong strand of protoplasm runs 

 along the axial cells from pit to pit. In this strand the nucleus is occasionally 

 suspended ; more often it lies over the pit at the base of the strand. 



In Dasya coccmea, the branches of limited growth run out into pointed 

 uncorticated filaments, the cells of which are large. Across the vacuole of these 

 cells running from pit to pit occurs a thread of protoplasm much more delicate 

 than the corresponding structure in Ceramium. 



In Gallitlmmnion byssoides, threads of protoplasm radiate from a cushion lying 

 over the pit and end blindly on the vacuole. These threads are in incessant move- 

 ment, swinging over, bending on themselves, and extending or retracting. All these 

 phenomena point to the great physiological importance of the pit-communicatioii 

 between cell and cell. 



3. On Reproduction in Dictyofca dichotoma. By J. Lloyd Williams, 

 Assistant Lecturer and Demonstrator in Botany, I^orth Wales Univer- 

 sity College, Bangor. 



1. Dictyota is an annual. In this country it germinates during the summer, 

 remains small during the winter, grows very rapidly in June, and begins to form 

 its reproductive cells in July. 



2. The tetraspores are produced throughout the season, and all stages may be 

 found together on the same plant. The sexual cells, however, show a remarkable 

 periodicity. The formation, maturation and liberation of each crop occupies a 

 fortnight, the interval between two spring tides. The sori are formed during neap- 

 tides, and the cells are liberated during, or immediately after the highest spring- 

 tides. 



3. When liberated the oospheres are not invested with walls. In this condition 

 they strongly attract the antherozoids, become fertilized, and at once start germi- 

 nating. The plantlets are similar to those figured by Thuret as resulting from the 

 germination of the tetraspores. 



4. If not fertilized the eggs lose the power of attracting antherozoids, they form 

 •walls, and, as already described by Thuret and Bornet, they germinate partheno- 

 genetically. After one, or a few divisions, sometimes accompanied by formation 

 of rhizoid rudiment, the process stops and the plantlets die. 



5. Towards the close of the season some sori fail to mature within the usual 

 period, and the crops become leas regular ; the same effect is brought about during 

 very cloudy and cold summers. 



6. The same conditions bring about sterilization of certain of the sexual cells. 

 Thus, patches of cells within the antheridise sori fail to divid^. Cells at the margins 

 of female sori remain barren, so that the usually borderless sori acquire partial, or 

 even complete borders. 



7. There are strong reasons for concluding that the factor which determines the 

 maturation and liberation of the sexual cells, and the fertilization of the oospheres, 

 is the amount of the illumination to which the plants are subjected. 



8. The cytology of the reproductive cells will be described as far as it has been 

 made out. 



4. On the Origin of Eailway-hank Vegetation. By S. T. Dunn. 



The surface of embankments and cuttings on English railways becomes covered, 

 after some years, with the same vegetation as can be found on any grassy slope in 

 their neighbourhood. Mixed with this, however, may usually be seen a certain 

 number of species of distant origin. The bare earth of the new embankment gets 

 sown with wind-blown seeds, both cuttings and embankments being likely to 

 arrest their flight and to afibrd a footing to even those which cannot compete suc- 

 cessfully with the native species. Seeds, also, which were in the earth used for 



