— 192 — 



of branchlets is almost the same in both plants, but the latter are in om- 

 plant much more spreading. As to the tentacula they are quite evident 

 in B. Siamensis, but they seem to occur less numerously than in B. coacta. 

 The joints in the different parts of the frond of B. coacta are tolerably 

 equal in length, while in our plant they generally vary not inconsiderably 

 in length in one and the same part of the frond. Besides the joints of 

 the primary filaments of B. Siamensis are thicker than in B. coacta. 



By examination of material preserved in alcohol I can confirm the 

 opinion uttered with some caution by Murray, who examined only dried 

 specimens, (of B. coacta), that the chromatophores agree wholly with those 

 which Schmitz has described for the genus Siphonocladus. (see Engl. u. 

 Prantl. Pflanzf. 1. p. 147, fig. 98). 



Koh Kahdat, in 1—2 fathoms water (coral-sand.), 



Dasycladaceae. 



Acetabularia Lamx. 



25. * A. major v. Mart. 0. Asiat. Tange p. 25. t. 4; v. Solms-Lau- 

 bach Acetabul. in Transact. Linn. Soc. 1895, Nr. 6. — De Toni Syll. I. p. 419. 



The splendid well developed plants agree well with this species, 

 except in that the stalks are somewhat longer (up to 10 cm.) than those 

 described and figured by v. Martens which difference is, I think, of 

 no importance. 



The disk measures 2 cm. in diameter and the rays vary in number 

 from 70 to 80. 



Abundant in the Koh Chang-Strait on rocks, stones, piles etc. between 

 tide-marks. 



Area: Siam (Simaharadscha) ; Timor; N. Guinea. 



Phaeophyceae. 

 Fucaceae. 



Sargassum Ag. 



26. S. polycystum Ag. Syst. p. 304; De Toni Syll. III. p. 103. — 



S. brevifolium Grev. 



Koh Kahdat, in 1— 2 fathoms water, attached to stones. 

 Area: Common in the Indian and Pacific Oceans. 



Cystoseira Ag. 



27. €. latifrons Kg. Tab. phyc. X. p. 22, t. 60; De Toni Syll. III. p. 176. 

 Perhaps the same species as C. proliféra J. Ag. 



Koh Kahdat, in 1—2 fathoms water, attached to stones. 

 Area: China; Timor; Tropic. Australia. 



