tnt.-] M CAROUSE ISLANDS AXD AUSTRALIA. 83 



I have referred the present plant to Cystoseira articulate Kg. 

 (=Hormophysa articulata Knetz.) by making comparison with Kuetzing's 

 illustration given in his Tab. Phyc. XL t. 61. The frond is furnished 

 with broad and serrated wings (10-15 mm. from the midrib.) which are 

 truncated above and attenuated below. The terminal portion of branches 

 are articulated into two, three or more joints which are inflated into tri- 

 quetrously marginated air-vessels, in the wall of which we find conceptacles. 

 In one and the same conceptacle, both male and female cells are situated. 

 These characters, especially those of reproductive organs, well qualify the 

 present plant to be ranked in the genus Cystoseira and the external ap- 

 poarence of the plant agrees with that illustrated by Kuetzing. 



Now, there are four or five plants very closely related to the present plant, 

 viz : Cystoseira triquetra (L.) J. Ag., Cyst, prolifera J. Ag., Cyst. laUfrons 

 Kuetz., and Hormosira 1 articulata (Forsk.) Zanard {^Cystoseira articulata 

 J. Ay.). Of the four species enumerated there seem to exist some con- 

 fusions, chiefly owing to the ignorance of conceptacles. I was fortunate 

 enough to detect conceptacles in the plant in question and thus in some 

 degree to clear up the confusion hitherto left among the related species. 



Cystoseira triquetra J. Ag., is distinguished from the allied plants by 

 the narrowness of equally broad wings and by haviug branches arising 

 from the edge of the wing. Cystoseria prolifera J. Ag., one of broadly 

 winged allies, is separated by having air-vesels swollen up near by midrib 

 and also by having conceptacles disposed in two curved rows on both 

 sides of the midrib in the membrane of ramuli. Cystoseira latifrons 

 Kuetz., which is more closely related to Cystoseira prolifera J. Ag. by 

 having receptacles in oblong leaves, is separated from it by having wider 

 trifarious wing and by the scarcity of air-vessels, if not always wanting, 

 as it appears from figures of Kuetz. Tab. Phyc. XL t. CO fig. 2. In De 

 Toni's Syel. Alg. Ill, p. 176, Hormophysa articulata Kg. is regarded 

 as a synonym (with ? mark) under Cystoseira latifrons Kg. But if my 

 identification is proved to be not in error, it should be separated from it 

 by the character of receptacles. 



Thus far, the differences having been noticed between Hormophysa 

 articulata Kg. and other three related species, there remains the ques- 

 tion whether Hormophysa articulata Kg. is diffrent from Hormosira ? 

 articulata, Zart. or whether the latter is same as Cystoseira prolifera 

 J. Ag. or Cyst, triquetra J. Ag. Sorry to say, I have been unable to see 

 either the specimens or illustrations of Hormosira ? articulata ; all that 

 I could do is to do with the diagnosis <nven in the referrences. As far 



