MR. G. MURRAY ON NEW SPECIES OF CAULERPA. 211 
С. cactoides when he founded his species. Не expressly says, ** Cette езрёсе, qu'à la 
première vue on pourrait confondre avec plusieurs autres de la deuxidme section 
d'Agardh *, se distingue de toutes par la position „distique de ses pinnules, et par 
conséquent appartient à la première section, à celles des Tazciformes. Elle diffère done 
des С.С. clavifera, cactoides, ete., absolument," &c. (Voyage au Póle Sud, Dumont 
D'Urville, vol. i. p. 15, tab. 6. fig. 2.) 
We need, therefore, hesitate no longer as to the identity of these species. С. сасіоійез, 
however, is а variable form, and this is shown especially by a specimen collected by 
Mr. George Clifton, R.N. (whose work in collecting the Algæ of Western Australia was 
so handsomely recognized by Harvey in many ways), and recently presented by him to 
the British Museum with his collection of Algæ. It has been mentioned above that 
C. cactoides is distinguished by the possession of an annulate stalk, while it may be 
added that the type and other specimens examined by me have a terete and smooth 
surculus. Mr. Clifton's specimen (Pl. LII. fig. 8) has not only this character of stem, 
but the surculus is similarly annulate, and the fronds are tall and unbranched. I have 
therefore resolved to regard this as a variety of C. cactoides. 
CAULERPA CACTOIDES, Ag., var. GRACILIS (Plate LII. fig. 8); frondibus a surculo 
repente annulatim constrieto erectis simplicibus, elongatis, gracilibus. 
Hab. ad oras occident. Novee Hollandisze, Clifton ! 
Before leaving the history of this species, I should like to add a remark which I am 
sure will interest the Linnean Society. It has been said that the original specimen of 
C. cactoides is the one collected by Robert Brown. Не had called it, as Dawson Turner 
says, by the specific name of “ Opuntia,” but Turner does not allude to the generic name 
used by Brown, viz. Actaia. In those days when most Algs were reckoned under Fucus, 
Brown had not only separated this and other forms by such names in his herbarium, but 
the truly remarkable thing is that he reserved this name Actaia for Siphonec, and 
further he applied it to them however diverse their outward forms. Let me give an 
example—he calls Polyphysa peniculus * Actaia peniculus," and the observation proves 
that he, at this early date, not only recognized the separate character of the Siphonee 
from other Algs, but he traced this character through most diverse forms. Brown 
never published this observation, nor can I find any manuscript of his treating of it ; 
but it exists in his herbarium in his own handwriting, and its significance is plain 
enough. It is interesting, therefore, to put on record now the fact that this great 
botanist, in addition to his other achievements, first perceived the separate character 
of this interesting group, and founded it (though privately) in his own herbarium under 
the name of “ Actaia.” 
Closely related to C. cactoides is another form new to science. It was collected 
in Ceylon by the late W. Ferguson, and is no. 415 of his herbarium (as distributed). 
Dr. Grunow has recognized by a MS. name the distinct character of this plant, for 
which he has proposed the name of var. Fergusonii. However, it differs not only in 
* Те. C. Agardh. - 
