228 BRITISH CORALLINES 



3. HALIMEDA, Lamouroux. 



Halimeda, Lamour. Cor. Flex. 302. Flem. Brit. Anim, 51.5. 

 ScHWEiG. Handb. 437 — Flabellaria, Lam. Anim. s. Vert. ii. 342. 

 Blainv. Man. 550.— Corallinee pars, Lin. Soland. 



Character. Coralline plant-like., branched tricTioio- 

 mously, fan- shaped^ the branches jointed., very much com- 

 pressed : crust thin and calcareous ; axisjibrous. 



According to Link Halimeda is the type of a family of 

 corallines which he names Halimedece. He says that when 

 these bodies are deprived of their calcareous cnist, they exhibit 

 a lamellated or membranous structure ; and no trace of po- 

 lypes is discoverable even at those points where analogy would 

 lead us to look for them. The crust is friable like chalk, and 

 it is sometimes found on the inner surface as well as on the ex- 

 terior. All the genera of the family have much the same struc- 

 ture. The genus Flabellaria of Lamarck embraces propei'ly two 

 genera, — the Udotea of Lamouroux and his Halimeda. The 

 latter is jointed, with flattened articulations, calcareous interior- 

 ly, and filled with a fibrous pith by means of which the articu- 

 lations are threaded together. The Halimeda opuntia has been 

 examined very carefully, and in a fresh state, by M. Schweig- 

 ger. By the aid of the microscope, he ascertained that the 



