DIV. I 



THALLOPHYTA 



379 



may take on an amoeboid condition in which it exhibits changes in 

 form and creeping movements. In other cases slender processes or 

 pseudopodia may be put out and again 

 withdrawn as in the Rhizopoda. These 

 assist in the absorption of solid particles 

 of food (Figs. 303, 309). 



Most representatives of the group live 

 as naked, free cells ; others form more or 

 less complicated cell-colonies held together 

 by mucilage, or they possess peculiar 

 stalked or unstalked firm investments 

 sometimes with siliceous or calcareous 

 skeletal structures. 



Sexual reproduction is wanting. Multi- 

 plication takes place by longitudinal divi- 

 sion, and in many species thick -walled 

 resting spores or cysts are produced. On 

 the germination of these, after division of Flo> m5 ._ H y drU rus foetidu*. 



the Contents, a number of daughter Cells of a branch of the colony enclosed 

 may be liberated (Fig. 308 B). * mucilage. (After BEBTHOI.D.) 



B, Swarm -cell. (After KLEBS.) 



The Chrysomonadinae are an important group (From PASCHER, Flagellaten.) 

 of the Flagellata, to which belong Chrysamoeba 



(Fig. 303) and the colonial form, Dinobryon (Fig. 304). They are characterised by 

 their radial structure and by their chromatophores which are usually brownish 

 yellow, less commonly red or blue green, and form a special carbohydrate 



FIG. 306. A, Distephanus speculum. (After BORGERT.) B, C, Calyptrosphaera insignis from 

 the Adriatic ; B is in optical section and C in surface view, (x 1600. After SCHILLER.) 



(leucosin). Hydrurus foetidus (Fig. 305) is an example of a more complex 

 member of the Chrysomonadinae. Its cells are associated in colonies as long 

 branched mucilaginous filaments which may be 30 cm. in length and are attached 

 to stones in running water. Numerous cells without cilia are embedded in the 



