Ser. RiioDosrKRME.E. Earn. Helminthodadea. 



Plate CCXXVIII. 



GALAXAURA OBTUSATA, Lama^. 



Gex. Char. Frond dicliotomous, thinly incrasted with carbonate of lime, 

 constricted as if jointed, or continuous, composed of longitudinal, 

 colourless, interwoven, and anastomosing medullary filaments, and 

 closely placed, inflated or tabular, coloured /)er7;j/^mc cellules. Fruit 

 uiiknown. — Galaxaura {Lamx.), a classical name ; one of the 

 Oceanidse of Hesiod. 



Frons dicJiotoma, calcareo-incrustata, articulato-constricia v. continua, plus minus 



transverslm rugulona, ex fills medullaribus tenuibus liyalin'is lofigitudinalibus 

 iittertextis anastomosaidibm, et celluUs pcriphericis subuiiiseriatis coloratis in- 

 fiath Uberis v. comjdanatis, arete cohcereutibuSjfurmata. Fructus ujnotm. 



Galaxaura ohtusala ; dichotomous, fastigiate, constricted at the nodes as 

 if jointed ; articulations oval or obovate, the uppermost oblong. 



G. obtusata ; dichotoma, fast'igiata, articidato-constrlciu ; articulis ovalibits v. 

 obovatis, supremis oblongis. 



Galaxaura obtusata, Lamx. Pol. Flex. p. 262. Kilts. Sp. Ahj. 529. 'Harv. 

 in Hook. Fl. Tasm. v. 2. p. 317. 



CoRALLiNA obtusata, Fll. and Sol. t. 22./. 2. 



Alysium Holtingii, Ag. Sp. Jig. v. I. p. 433. 



Ulva Holtingii, ^fe^•L 



Hab. West Australia, G. Cliflon. Norfolk Island, Dr. McWilliam. 



Geogr. Distr. Tfie tropical Ocean, in all longitudes. Bahamas. West In- 

 dies. Pernambuco. Port Natal. Algoa Bay. West Australia. Pacific 

 Islands. 



Descr. Root a tuberiform mass of interwoven fibres, more or less covered with 

 calcareous deposit. Fronds very many from the same concrete base, 4-8 

 inches long and nearly as much in the expansion of the branches, flabelli- 

 form in outline, regularly dichotomous, fastigiate, thinly coated with a 

 smooth enamel of carbonate of hme. The frond throughout is strongly 

 contracted at the nodes into bead-like portions or spurious articulations ; 

 these are oblong, obovate, or linear, in different parts of the frond ; the very 

 young ones are globose, the old ones are 3 -4 times as long as broad. The 

 axils are wide and the apices obtuse. No fruit has been observed. The 

 frond is traversed by many longitudinal filaments, which emit dichotomous 

 branches towards the periphery or outer wall of the branch. This is formed 

 of two or more scries of iiexiigoual or rouudi^sh angular cells, and the surface 

 composed of flattened tabulated cellules. The colour is a dull livid-jjurple, 



