G. HALIMEDA. 139 



THICK. 



2. Halii\ieda incrassata. Articulations convex, 

 compressed, or flat, and of many shapes. 



Caribean Sea. 



MANY-STALKED. 



3. Halimeda multicaiiUs. Lower articulations 

 nearly cylindrical ; upper ones kidney-shaped, flat- 

 tened and lobed. 



irregular. 



4. HalIiAIEDA 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. 



