36 
THE SEAWEEDS 
pinnae are patent and opposite, narrow, subcylindrical, incurved at the 
tips. Thus the assimilator has the appearance of a delicate feather. 
Found hv Dr. A. Engelhardt in Guichen or in Rivoli Bay. It. was 
formerly called C. plwnaris Forskaal, but the present name has priority. 
It is widely distributed in tropical seas, as on the Barrier Reef, but it is 
remarkable to find it so far south. However, Dr. Engelhardt ’s specimen was 
determined as C. plumaris by Madame Weber van Bosse, the distinguished 
authority on the genus. 
Fig. 17 . — Caulerpa sert’ulcLrioides. 
Section Hippuroideae. 
In the section Hippuroideae the green fronds are large and conspicuous, 
each consisting of an elongated rachis bearing long slender ramenta, much 
in the same way as the vertebrated axis of a horse’s tail bears the hairs. 
All are confined to the south coast of the continent and Tasmania. The 
species may be recognised by the following key : — 
a. Ramenta not arranged in distinct 
longitudinal rows but spreading 
brushwise in all directions. 
b. Ramenta simple C. longi folia C. Agardh. 
bb. Ramenta pinnate C. obscura Sonder. 
