•r velutinous), flattened above and in structure passing gradually into 



the flabellum. 



1 ,,,. , .., ... , ate, rarely cuneate, rarely auriculate base, subrotundate to 



flabelliform, a m. long, and 5 cm. wide, greenish-white, zoned, surface minutel) and 



longitudina ate above, velutinous or spongiose towards and at base, margin 



,:i\ lobate. 



15 35 f* in diameter rarely 45 /ut), slightly caJcified, radiating from 



peatedl) dichotomously branched, unevenl) constricted above '-ach dicho- 



;, pluriseriate, usually densely conglutinated together by calcareous deposit. Fila- 



of frond bearing a few short, simple, lateral branchlets or fibulae (compare 



rit. pi. XLIV, fig. I l 



Filaments ut' stipes bearing lateral appendages, dichotomously divided and terminated 

 >mall, short, obtuse, sometimes ovoid, apices. [Figs. 1, 4, .17, 48]. 



I'his species (see fig. 1) is the parallel in the [ndian < )cean of the West Indian U. 

 xglutinata (fig. 44), trom which it differs essentially in having the supra-dichotomial con- 

 strictions of its frond -filaments very unevenly situated (compare hg. 47 with hg. 45). Also l 

 orientalis is more slender tlian the West Indian species, and its frond-filaments have a 

 slightly smaller diameter. 



It should be noted that U. orientalis (fig. 17) and its ally, U. glaucescens, as well as 

 U.indica and U. palmetta, all inhabitants of the Indian Ocean, have the characteristic uneven 

 supra-dichotomial constrictions, which distinguish Chlorodesmis comosa (figs. 72. 73/M oi the 

 Indian and Pacific Oceans. The West Indian species, U. conglutinata and U. cyathiformis, 

 are distinguished at once by their even constrictions. 



The distribution of U. orientalis lies between Timor, Celebes, and Macclesfield Bank on 

 the east and Zanzibar and Natal on the west. The number of specimens in the Siboga collections 

 shows that the plant is not uncommon in the Malay region. The Natal plants are deep green 

 in colour and diverge from the type in having stouter frond-filaments reaching 45 ;j. in 

 diameter (bul with the uneven constrictions typical of U. orientalis), and in the stouter apices 

 of the lateral appendages of the stipes-filaments. 



The geographical distribution of U. orientalis is within the Indian and Pacific < >ceans. 



7. Udotea explanata n. sp. 



Syn. \Flabellaria Palmetta Kützing Tab. Phyc. VIII. 1858 p. 12, tab. 27. fig. 1. 

 ? Udotea Palmetta Sonder <-x Kützing loc. cit. 

 r Udotea Kützingii De Toni Sylloge Algarum I. 1889 p. 511. 



//<i/'. Indic. Siboga Expedition. Celebes! ? Arabian Gulf, Sonder. 



I'lant about 7.5 cm. high. Stipes 1.5 cm. high, cylindric below and 2 mm. thick, flat- 



to a width of 5 '> mm. and in structure passing gradually into the flabellum; 



pongy-velutjnous, continued on to the base of the frond for a distance oi 



2 m m . 



