G. HALIMEDA. 
139 
THICK. 
2. Halim eda incrassata. Articulations convex, 
compressed, or flat, and of many shapes. 
Caribean Sea. 
MA NY-STALKED. 
3. Halimeda multicaulis. Lower articulations 
nearly cylindrical ; upper ones kidney-shaped, flat- 
tened and lobed. 
IRREGULAR. 
4. Halimeda irregularis. Articulations of va- 
rious shapes, from two to three millemetres in length or 
breadth ; height of the Polypidom four or five centi- 
metres. — Plate 11. fig. 7. 
The Antilles. 
THREE-TOOTHED. 
5. Halimeda tridens . Articulations flattened, 
and in three lobes. 
American seas. 
OPUNTIA. 
6. Halimeda opuntia. Articulations compressed, 
fan or kidney-shaped, undulated on the borders. 
Mediterranean and Atlantic. 
TUNA., 
7. Halimeda tuna . Articulations plain, and nearly 
round.-— Plate 11. fig. 8. a. b. 
Mediterranean. 
