1 8 8 VOL VO CINE&. PART n. 



the hyaline globe, and by their vibrations, they make it 

 rotate about an axis perpendicular to the plane of its 

 equator, and move actively through the water. Each of 

 the primordial cells, which are green with a spot of red in 

 the centre, secretes a cellular covering, and they swim 

 about in the interior of the globe as free cells. Even- 

 tually they escape either by fissure of the globe, or by 

 its gradual dissolution. After swimming about for a 

 short time they become motionless, lose their cilia, and 

 sink to the bottom as green still spores. 



If, after being dried, water be poured on one of these 

 green still spores, it takes up the water, its contents 

 become closely granular, and fill the whole membrane of 

 the spore. Then it divides, first into halves, then into 

 quadrants or heart-shaped segments, meeting in a point 

 in the centre of the membrane. These quadrants are 

 ultimately divided into 8 wedge-shaped segments, whose 

 contour lines, like the spokes of a wheel, meet in the 

 centre, and each gets a pair of cilia. The coloured 

 matter is driven back in each individual towards the 

 thick end of the wedge as if by centrifugal force, and 

 a colourless plasm remains in the points or beak. These 

 disappear, a cavity is formed in the centre of the disc, 

 the eight bodies assume the form of a wreath in close 

 contact, and the original cilia, which continue to vibrate, 

 cause the rotatory and progressive motion of the whole 

 organism. 



Sometimes the eight globular bodies have been seen 

 to divide into a number of extremely minute motile 

 cells, while yet within the parent globe. These gonidia, 

 as they are called, are, with a few exceptions which may 

 reproduce the plant, believed to perish when they come 

 into the water. 



The division of the primordial cell of this plant is 

 confined to a certain time of day; it begins towards 

 evening, and is completed the following morning, and 



