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CLASS II. — ORDER II. 
HALIMEDA. 
Polypidoms plant-like and articulated; articula- 
tions flat or compressed, very rarely cylindrical, gene- 
rally fan-shaped ; axe fibrous ; rind cretaceous, and 
usually rather thin. 
The Halimedas are unlike any genera of the pre- 
sent order ; the interior and exterior substances can 
alone establish their place in it. 
They are found in the seas of the warmer latitudes ; 
they sometimes, though rarely, appear on the southern 
shores of the Mediterranean, increasing in number as 
you approach the equatorial seas. They are abun- 
dant in the Antilles. 
The Corallinas surpass them in variety and bril- 
liancy of hues ; although green in the bosom of the 
sea, they become white on exposure to light and air. 
They rarely exceed a decimetre in height, and 
are never below five centimetres. 
The Halimedas are sometimes parasites on the 
Thalassiophytes, but more frequently adhere to 
rocks or solid sands by numerous fibres of unequal 
length. 
They are found mixed with the Corallina of Cor- 
sica, and appear in no wise to alter the anthelminthic 
and absorbent qualities of that Polypidom. 
NECKLACE-FORMED. 
1. Halimeda monile. Lower articulations com- 
pressed, convex, cuneiform, and oblong ; the upper 
ones nearly cylindrical. 
American seas. 
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