170 Murray and Boodle. — On the 
Zanardini’s genus is not only merged in Areschoug’s, but the 
type disappears from the group of Siphoneae. At first sight, 
however, it looks so like certain members of the group that 
there is ample room for mistake. It may be recalled indeed 
in justification of Zanardinfs opinion that in 1886 one of 
the present writers found with the Kew specimens of 
vS. vaucheriaeformis a note by the late Professor Dickie, pro- 
posing to found on them a new species of Rhipilia — though 
subsequent examination, as 
shown by his own her- 
barium in the British Mu- 
seum, enabled him to cor- 
rectly place the form under 
Areschoug’s name, which it 
bears in his published list 
of Algae of Mauritius \ 
This likeness will be under- 
stood from the following 
description. 
The thallus of vau- 
cheriaeformis consists, as 
Areschoug pointed out, of 
long, filiform tubes so inter- 
woven as to form a number 
of irregularly dichotomous 
branches, the whole recalling 
in appearance a digitate 
sponge. These branches are 
of the thickness of well- 
grown specimens of C odium 
tomentosum , though another species about to be described re- 
sembles this Alga much more strikingly. The tubes of which 
the branches are composed are septate below, and short lateral 
branches are given off at about right angles from the cells, 
often on the same side of the filament from three or four 
Fig. 8. Filament of Spongocladia vau- 
cheriaeformiS) Aresch. 
Linn. Soc. Journ. Bot. xiv. 
