32 
THE SEAWEEDS 
be superposed or grow in a loose rosette. The greater part of each frond 
is monostromatic. The frond forms a membrane of small close-fitting sub- 
globose 5 or 6-angled cells. The adjacent cell walls are thick and form a 
close network. The endochrome is fluid and gives an attractive dark-green 
appearance to the fronds. 
71. sericea occurs in Western Australia, South Australia, Victoria, and 
on the north coast of Tasmania. It, grows on rocks near low-water mark 
and is sometimes more or less bleached by exposure to sun and air. 
Other species of Dictyosphaeria are found on the Barrier Reef and Lord 
Howe Island. In all of these the diameter of the cells is twice that of the 
cells of D. sericea. 
Order SIPHONEAE. 
Constructed of only one cell. 
Family BRYOPS1DACEAE. 
BRYOPSIS Lamouroux. 
Frond filiform, tubulous, elongate, branching; the upper ramuli 
distichously pinnate or imbricate; zoogonidia very numerous, biciliate. 
Fig. 15 . — Bryopsis pkimosa. 
