288 



ALG^E 



zoosporange, no conjugation of swarm-spores having been observed. 

 Klein (Bot. Zeit, 1880, p. 782) has detected fine proteinaceous crystal- 

 loids in Dasycladus (Ag.) and other allied forms. To this family belong 

 also Polyphysa (Lmx.), Cymopolia (Lmx.), and some other genera. 



FIG. 255. Polyphysa penlculits R. , 

 Br., with whorl of zoosporanges, sp 

 (magnified). (After Agardh.) 



FIG. 256. Caulerpa prolifera. Lmx. (natural size). (After Reinke.) 



ORDER 4. SIPHONOCLADACE^E. 



This order comprises a number of very remarkable green algae, mostly 

 inhabitants of warm and shallow seas, characterised by the thallus con- 

 sisting of a single cell which is often of very great size and much branched, 

 differentiated into a root-like and stem-like portion. The undivided cell 

 very commonly contains a large number of nuclei ; and the cell-wall is 



