20 



U.uxU. Prain\ ■ — Gulf of Manaar, Thurston\ - Singapore, Ridley\, n". 101. -- Borneo, 

 Kjellmanl, Wittr. et Nordst. Alg. exsicc. n". 341. — Maumeri, Flores, Weber van Bosse\, 

 n". 1020. — Macassar, Weber van Bosse\ — 

 Siboga-Expedition. North Ubian, 16.2 m.! — Elat, Great Kei Island ! — Jedan Island. 10.8 m. ! — 

 Banda! — Sailus ketjil, Paternoster Islands! N. E. corner of Timor, 36 — 54 m. ! — 



Saleh bay, Sumbawa, 14 — 18 — 28. cS m. ! — Bawean Island, 28.8 m. ! — Kabala dua, reef! — 

 Statiën oi 1 . 120 m.! - Noimini, S. coast of Timor, reef! - Kangeang Island! - - Dobo, 

 Aru Islands! - Sailus-besar, Paternoster Islands! — Sanana, Sula-Besi ! — Roma Island, 

 reef! Salibabu, Lirung, reef! - - Binongka Island, reef! - - Island Tanah-Djampeah, 30 



m. ! — Siau Island! — Taam Island t 18 m. ! — Savu! - - Labuan Tring, Lombok! - 



PACIFIC. — China Soa, Baume\ Herb. Mus. Paris sub nom. H. triloba Decaisne. — Philippines, 

 ( uming\, 2235. " Challenger"'] — Parry Shoal, Arafura Sea, Basset/ Smith ! — Solomon Islands, 

 Guppy\ - New Guinea, Karnbachl, n". XXVIII. -- Admiralty Islands, " Challenger" '! — 

 Ponape Island, Caroline Islands, " Albatross" '! Christian ')! — Caroline Islands, Mertens\ — 

 Funafuti, Davidl n"\ A. 3 1 pro parte, A. 54, A. 58, B. 5, B. 10. "Albatross" ! — Friendly Islands, 

 Harvey\ n°. 92. — Fiji, Herb. Mus. Brit\ — Tongatabu, " Challenger'' '! Graeffe\ Home\ — 

 Upolu, Herb. Mus. Brit'. — Tahiti, * Challenger" \ Niau, Paumota, " Albatross 1 ' '! — Fakarawa, 

 " Albatross" '! — Rangiroa, Mohegan reef, " Albatross'' '! — Honolulu, " Challenger' '! — 

 Sandwich Islands, Home\ — Capricorn Group, Jukesl — 



Varying from a straggling plant up to 25 cm. long, sparingly branched in one plane ; 

 to a thick tuft with numerous radiating branches; with all intermediate forms. 



Joints very variable; more or less flat, deeply calcified, sessile or stalked 2 ): discoid, cordate, 

 trilobed, or broad in the middle and narrowed at both ends, clearly or indistinctly ribbed. Size 

 varies to about 12 mm. long, 20 mm. broad, 75 mm. thick between the ribs. 



Filaments of central strand fuse in pairs at apex of each joint ; fusion incomplete, limited 

 to surface of contact of lateral walls. Each filament after separation continues for short distance 

 unbranched, branching later di-or trichotomously. 



Peripheral cells 20 — 50a across, in surface view; rarely 60 u. long; side walls in contact 

 for about Vis °f their length. 



forma typica. 



Often forming an irregular mass, much branched and in more than one plane ; distinctly 

 ribbed, so that the rounded upper margin appears waved ; lower margin forming more or less 

 of a right angle with the miclrib ; joints not overlapping each other (fig. 19). 



forma cordata. 



//. cordata J. Ag. 1. c. 

 Joints rounded, prolonged below into two well-marked auricles, which overlap the lower 

 joint (fig. 21). 



forma triloba. 



II. triloba Decne. 1. c. 

 Joints markedly trilobed, segments deeply cut, thick, ribs distinct (fig. 20). 



1) Dr. Christian notes about this specimen: ""Kom". From Mutok Harbour — S. Coast. A narcotic seaweed found un the 

 detached reefs in the lat;"'!- ying the Raraial 01 rentumoi, a species of jellyfish Uviug \\\ the cracks uf the coral". 



2) The stalk in //. Opu/itia, when present, is not specially differentiatcd, as in //. cuneaia but is merely the narrovv inferior 



joint. 



