1^2 B. Millard Griffiths. 
13, E), or when the organism is distorted with re-agents so that the 
lobes are more or less divaricated (Fig. 15, A). 
There is a large pyrenoid in the chloroplast, situated in the 
thick posterior portion, behind the fusion of the lobes. It is sur¬ 
rounded by a starch sheath (Fig 13, A, B, C). Behind the pyrenoid 
in the line of the cell axis is a small flask-shaped cavity, which 
(cilia not shown). F-H, Chlamydomonas sp. F, Vegetative stage; G, Large 
mother-cell; H, Mother cell with two daughter-cells formed by longitudinal 
division, n, nucleus ; p, pyrenoid ; p.c., posterior cavity in chloroplast ( x 800.) 
opens out at the posterior extremity of the chloroplast (Fig. 13, A, 
Fig. 14, A). In some specimens the latter is divided into four 
blunt lobes, but this is not usual (Fig. 13, D). 
I was unable to find a pigment spot in any of the many 
specimens examined. Neither was I able to find vacuoles at the 
base of the cilia. The search for the latter is made very difficult 
on account of tiie cup-shaped depression at the anterior end of the 
cell, in which the cilia originate, and the organism cannot be made 
to take up a position favourable for observation. 
Division. Vegetative multiplication takes place by means 
of longitudinal fission. This was commonly observed in all the 
collections examined. The ordinary vegetative cell is at first 
elongated (Fig. 14, A). It soon becomes broad and heart-shaped 
