- 198 



(/on;! til 1 1 divisis) per frondem sparsis. Gystocarpiis ? ? — Ghartae 

 adhaeret. 



The plant represents a true Rhabdonia by the structure of the frond, 

 characteristic for this genus, together with the zonate tetraspores. Of all 

 the known species of Rhabdonia the new species seems to be most nearly 

 related to R. decumbens Grun. (Asken. Gazelle p. 46, t. 2). Even on rea- 

 ding the somewhat short diagnosis I had at first the conjecture, that the 

 two plants, although living in very distant places of the world, were identical, 

 but after having examined the figures of R. decumbens, I was convinced 

 of the impossibility of uniting the two plants under one specific name. 



Our specimens are so intricated and in part so closely attached one 

 to the other and also to small grains from the ground (pieces of shells 

 etc.), that it is very difficult and often even impossible to separate the 

 fronds without injury or to make a preparation of an uninjured com- 

 plete specimen. In the figures I have attempted to show the habit of 

 the plant, but it would require a great number of figures to give a 

 complete idea of the great variety in branching and of the diverse 

 arrangements of the prolifications and excrescences. These latter growing- 

 out from the margin or the tips of the segments (or of the prolifications) 

 and more seldom from the flat surface, are also of a very varying form, 

 sometimes they are like warts or little cushions, then they resemble 

 little teeth or roundish, simple or forked cilia, or more elongated and 

 variously divided ones, which fringe the margins or terminate the tips 

 of the segments. (Figg. 2 — 5 represent some different forms of the 

 excrescences). The frond is not strictly articulated (as in R. clavigera, 

 R. verticillata) but it is in part and in an irregular manner slightly 

 constricted and dilatated alternately, so as to make sometimes the mar- 

 gins of the frond unequal. The consistence of the frond is somewhat 

 gelatinous so that the plant adheres firmly to the paper. I have not 

 seen cystocarps. 



Koh Chang-Strait, in shallow water near Lem Ngob. 



Sphaerococcaceae. 

 Gracilaria Grev. 



45. G. coufeiToides (L.) Grev. Alg. Brit. p. 123; De Toni Syll. IV. 

 p. 431. — Fucus confervoides L. Spec, plant. II. p. 1629. 



Off Koh Kam in 10 fathoms water. 



Area: Widely distributed throughout all warm Seas. 



46. G. dura (Ag.) J. Ag. Alg. medit. p. 151 ; De Toni Syll. IV. p. 442. — 



Sphaerococcus durus Ag. Spec. p. 310. 

 Area: In almost all warm Seas, 

 f. prolificaus Reinb. n. f. 

 fronde admodum crassa, ramis et ramulis basi eximie constrictis, 

 prolificationibus evidenter petiolatis ex apicibus truncatis ramorurn 

 (fere flabellatim) egredientibus. 



