551 



NOTES. 



Brachiomonas submarina, Bohlin. 

 By the Rev. Eustace Tozer. 



Plate XIV. 



Since reading rny paper at the meeting of the Royal Microscopical 

 Society, February 1908, I have seen the note on this form pub- 

 lished by Mr. G. S. West, of Birmingham, in the Linnean Journal 

 for January. Mr. West kindly refers to my find, and after some 

 correspondence with him I have come to the conclusion that it 

 would be inadvisable to dissociate this alga T described from 

 Bohlin's Brachiomonas submarina in spite of certain differences. 



My observations will be seen to agree with Mr. West's up to a 

 certain point. Bohlin's description I have not seen. 



The alga then was found by me four years ago in brackish 

 water at Sheerness. My son also found it in rain-water in an old 

 boat. It is probable that the boat brought in the alga from the 

 sea, and the rain-water, becoming saturated with salt, provided a 

 suitable medium for development. 



The alga consists of a sphere arising from the surface of which 

 are five firm processes somewhat curved. These processes are 

 hollow, opening at the base into the sphere (plate XIY. fig. 1). The 

 outlines of the sphere are clearly seen when the contents divide. 



A rich green chlorophyll fills the sphere. It is somewhat 

 granulated and contains a fairly conspicuous nucleus. 



A remarkable fact with regard to the chlorophyll is that 

 when the alga is kept a few hours in the dark it contracts \v the 

 sphere, leaving the processes cp:iite clear. When the alga is exposed 

 again to strong light, the chlorophyll is seen extending into the 

 processes until only the tips are clear. 



It may be of interest to say that I have observed similar 

 expansion and contraction of the protoplasmic contents in the cells 

 of Melosira and Pleurosigma under similar conditions. In Mclosira 

 the protoplasm curls up and auxospore formation may thus be 

 induced. 



Brachiomonas is bi-flagellate, the flagella being thick, long, and 

 very active. The alga swims with a " trembling " motion, and a 

 crowd of the forms resemble the flight of a flock of swallows. The 

 five processes (four of which are of equal size, the fifth at the 



