76 



168. Cells single but arranged in groups within a mass of mucus. 



Each cell furnished with two cilia projecting out through the 

 mucous envelope. All the cilia move in unison, so that the 

 group is in constant motion. VOLVOCIXE.E. 



Cells not capable of locomotion. In time of fructification mostly 

 two celled. Cells often variously branching. Growing in tufts. 

 Sometimes the cells are associated into a spongy frond-like mass. 

 Growing in fresh water. VAUCIIERIACEJE. 

 Growing in salt water. 



Cells in multiplication remaining associated so as to appear like a 



branched thallus. VALONIACE.E. 

 Single cells so branching as to imitate stem, root, and leaves. 



Growing very large, 10 to 15 centimetres long. CAULERPE.E. 

 Thallus having root-like projections for adhesion to other bodies, 



much branched, with the fine branches so interlaced as to appear 



like a mass of cellular tissue. CODIE.K. 



169. Union affected by ordinary vegetative cells, not furnished with 



cilia. 170 



Union effected by similar, self moving, ciliated swarm cells. Cell 

 contents green. 



Microscopic one-celled plants. Cells becoming pear-shaped and 

 having numerous, root-like branches. Growing in mud, or in 

 partially dried pools, and capable of assuming various appear- 

 ances, according to the amount of moisture and light. 



Ihl'KOGASTREJK. 



Plants composed of many short cells united into threads which are 



cylindrical or bead-like. ULOTHRICACEJE. 

 Cells single but commonly associated in clusters. Fresh-water 



plants. 



Cells living singly or in clusters and surrounded by mucus. 



Cells associated in disc-like clusters or in hollow nets, not surrounded 

 by mucus. HYDRODICTYE.E. 



170. One-celled plants, though the cells often remain associated in 



thread-like clusters. 171 

 Cells united into threads. Of a bright-green color. 



