CHLOROPHYCEA 145 
DASYCLADACEA. 
General Characters—The thallus consists of an 
erect axial cell with no cross-walls, bearing whorls of 
lateral branches, some hair-like and sterile, others of 
definite growth and fertile. The shoot is attached 
by rhizoids to its substratum. Reproduction is 
effected after the conjugation of gametes. The 
order is naturally divided into at least two sub-orders, 
viz. Acetabulariew and Dasycladew. 
Acetabulariee. 
The Thallus.—The erect axis bears at its summit 
a disc-like cap, consisting of radiating chambers, 
which in the species of the genus Acetabularia (as 
Fic. 42.—Acieularia Schenckii naturui size. (After Solms-Laubach.) 
formerly defined) are united to each other laterally 
so as to form a firm disc. Other species were for- 
merly placed under Polyphysa, but that genus is now 
L 
