occurrence as it is in England. Subsequently, Agardh detected 
it in both the Adriatic and Mediterranean Seas, from various 
localities of whose shores I have received specimens, rather more 
luxuriant than our British plants, but not affording any essential 
distinctions. Mrs. Wyatt was the fortunate discoverer in 
England, in the year 1838, and it was first made known to British 
botanists in her excellent ‘Alge Danmoniensis’ under the 
expressive name Mesogloia moniliformis, which we regret cannot 
be preserved, owing to the prior claim of the comparatively 
unmeaning epithet bestowed by the first discoverer. 
By Bonnemaison it was referred to Batrachospermum, with 
which genus it perfectly agrees in habit, and has many points of 
direct affinity, but its structure, though similar in many respects, 
is not identical. Agardh originally placed it in Mesogloia, 
afterwards, less happily, in Grifithsia. Mrs. Griffiths was the 
first to suggest it might prove the type of a new genus, allied on 
the one hand to Dudresnaia, on the other to Batrachospermum, 
and the younger Agardh has accordingly assigned to it the name 
it here bears. It must be confessed, however, that, except for 
the very decided gelatine, and some difference in the conceptacular 
fruit (as described by J. Agardh), there is little to separate it 
from Callithamnion, to which genus it is united by Kiitzing. 
Were the ramelli opposite instead of whorled, the habit would be 
very similar to that of Cal. floccosum, and others of the same 
section. 
Professor J. Agardh describes the ‘ Favellidia’ as the only 
fruit with which he was aquainted, but I have never found them 
on British specimens, on which, on the contrary, fefraspores are 
commonly formed. These last are of very large size in proportion 
to the size of the plant, and have a structure exactly similar to 
that of the tetraspores of Callithamnion. 
C. attenuata is of extreme rarity on our coasts, having hitherto, 
as far as I am aware, been only found in the two stations given 
above. 
Fig. 1. CROUANIA ATTENUATA, growing on Cladostephus spongiosus:—of the 
natural size. 2. A branch. 38. Portion of the stem, with a whorl. 4. A 
filament from the whorl, bearing a tetraspore :—all variously magnified. 
