432 ^Ir Rattray 071 the Distribution of 



protuberances, by ^vbich tbe embryos early become 

 attacbed to tbeir substratum. The rbizoids are in some 

 of the mounted specimens wavy in outline, spread out in 

 a somewhat fan-shaped manner from their origin, are closely 

 placed, and possess somewhat ill-defined outlines. In 

 some small embryos they attain about one-third of the entire 

 length of the plants, but in most cases their extremities 

 have been broken off in the course of manipulation, and 

 their length is relatively considerably less. 



At this time the distinctly green and healthy appear- 

 ance of the numerous and undisturbed embryos in the 

 glass vessels was well marked, and they rapidly increased 

 in size up to November 20, when the observations were 

 stopped, and when the maximum length of some of the 

 specimens examined was 1*8 mm. The first stages in the 

 formation of lateral protuberances which, by further cell 

 divisions, would form ramuli, were not detected. Scrap- 

 ings taken from some of the submerged pieces of wood 

 were examined at intervals during the same period as 

 embryos germinating in the glass vessels, the average 

 maximum lengths and breadths of many specimens show- 

 ing the same progress in growth in both cases. In the 

 process of removal from the wood, however, the delicate 

 and intricate rbizoids were invariably injured, but as little 

 damage was done to the specimens as possible in their 

 removal and in the course of their manipulation on the 

 stage of the microscope. 



On the emission of the spores their movements were at 

 first very active. Under the microscope, when a light of 

 feeble intensity was transmitted from the mirror, the 

 movement did not appear to stop for at least two hours, 

 but with a somewhat stronger illumination the swarmpores 

 soon showed a tendency to pass into a more shady part of 

 the field ; when their activity under a moderate illumina- 

 tion had flagged to a considerable extent, the sudden 

 transmission of more powerful rays for a very limited time 

 stimulated to greater energy. 



Although I have not succeeded in determining satisfac- 

 torily the exact heliotropic tendencies of these swarm- 

 ipores, it is interesting to recall an observation by Borzi,* 



* Studi algologki, Messina, 1883. 



