15 



and even that, in the present imperfect state of our knovvledge of the fruit, must be considered 

 one of doubtful constancy ; so that in face of the great similarity of vegetative characters, there 

 is at present no satisfactory reason for maintaining the two species. I have however preserved 

 H. platydisca as a form, to denote one of the lines of variation, along which this species may develop. 



Through the kindness of Dr. Beccari I have been allowed to see the type specimen 

 of H. papyracea Zanard. the structure of which is identical with that of H. Ttina. The joints 

 are somewhat thinner and larger than those in forma lypica, and the plant must be regarded 

 as standing between forma typica and forma platydisca. 



The geographical distribution of H. Tuna shews a wider range than any other species 

 of this genus. It occurs in the Mediterranean, the Indian Ocean, North Atlantic and South 

 Pacific. lts southern limit is the Tropic of Capricorn. 



2. Halimeda cuneata Hering. 



H. cuneata Hering in Flora. 1846. p. 214. 



H. cuneata Kützing, Spec. Algarum 1849. p. 505. non Tab. Phyc. 

 H. cuneata De Toni, Syll. Alg. vol. I. 1889. p. 526. 

 H. obovata Kützing, Tab. Phyc. vol. VIII. p. 11. 185S. tab. 25. fig. I. 

 H. obovata J. Agardh, Till Alg. Syst. VIII. p. 86. 

 H. obovata De Toni, 1. c. 1889. p. 523. 

 H. versatilis J. Agardh, 1. c. 

 H. versatilis De Toni, 1. c. p. 524. 



H. macroloba Harvey, Phyc. Austr. Tab. CCLXVII et descript. pro parte. 

 H. macroloba Askenasy, Exp. S. M. S. Gazelle Th. IV. Bot. Alg. p. 14. tab. III. figs. 6, 8, 

 9, 10 tab. IV, 1 1. 



Plants varying in length to about 20 cm., slightly incrusted with lime, branching in one 

 plane, di-tri-or polychotomously. Root short, more or less bulbous. 



Joints sessile or shortly stalked, varying from elongate-cuneate to almost discoid, not ribbed, 

 margin ëntire, flat or undulating, sometimes thickened, recurved and grooved ; varying in size to 

 about 22 mm. long, 25 mm. broad, 1 L — -1 mm. thick in middle, and 2 1 /., mm. thick at margin. 

 Apex of joint sometimes slightly raised, giving the appearance of a cushion at the base of the node. 



Filaments of central strand fuse in twos or threes at the apex of each joint; one fila- 

 ment (rarely twoj resulting from each fusion, of varying length, with walls sometimes thick 

 and subtorulose, branching later di-or trichotomously. All filaments closely adhering at the 

 point of fusion. Peripheral cells irregularly hexagonal in surface view; 25 y, to 40 u. across, 

 about 100 u. long. Side walls of adjacent ceds in contact for 1 / 4 — 1 j 2 their length. 



Hab. INDIC. South Africa, Kraussl Herb. DickieX — Port Elizabeth, Cape Colony, Farquhar ! 

 SutherlandX Weber van Hossel Spencer \ — Port Alfred, Carr\ — ■ Natal, Herb. Hauck\ 

 Evansl Keil\ — Madagascar, Waters\ — Lasgori (Somali Coast) Hildebrandt\, n°. 3. - 

 South Arabia, Lunt\ — Nicobar Islands, Moravian Missïonaries in Herb. Mus. Brit\ - 

 Swan River, Lady Broomel — Fremantle, West Australia, Harvey !, Alg. Austr. Exsicc. 

 n". 562, sub nom. H. macroloba. — W. Australia, Askenasy ! — Rottnest Island, Markwell\ 

 Carnac Island, Clifton ! — 

 Siboga-Expeclition. Fau ! — Elat, Great Kei Island ! — Dongala. - - Bay of Pidjot, Lombok ! — 



Pacific. Lord Howe's Island, M' Donald\ — Matuku, Askenasy ! -- Queensland, Tully ! — 



