OF SOUTH AUSTRALIA. 
35 
C. denticulata DeCaisne (by many phycologists united with C. sccilpelli- 
formis) differs in that the lobes of the fronds are markedly denticulate, 
while those of the Australian species are quite entire; it occurs on both 
sides of the Atlantic, in the Red Sea and on the west coast of India. 
Fragments of C. scalp ellif or mis are not infrequently cast up on the 
beaches. 
Fig. 16 . — Gaulerpa scalp ellif ormis. 
Caulerpa sertularioides (Gmelin) Howe. 
A much smaller plant than the preceding, rarely attaining 5 cm. in height 
and mostly not half as high. 
The surculus is slender and smooth. The assimilators have a simple or 
branched petiole, and the fronds are pinnate from a terete rachis. The 
